@@ -37,6 +37,7 @@ Freebuff includes a curated model catalog. The regular picker currently offers:
 | **MiMo 2.6 Flash**          | Full and limited access | The default everywhere; balanced performance with image support   |
 | **GLM 5.3 Flash**           | Full and limited access | Deepest reasoning, unmetered                                      |
 | **DeepSeek V4.1 Flash** | Full and limited access | Fast coding and tool use, unmetered                               |
+| **DeepSeek V4.1 Flash Fast** | Full access        | Fast mode: the same model on DeepSeek's own API, splitting work across parallel subagents and verifying the result; priced on DeepSeek's peak and off-peak hours |
 | **GPT-6 Luna**              | Full access             | Strong all-around with native images; runs on OpenAI flex capacity |
 | **MiMo 2.6 Pro**            | Full access             | Xiaomi's stronger reasoning model, with image support |
 | **Solar Mini 4**            | Full and limited access | Upstage's fast, compact model; 524K context, text only |
 
@@ -37,6 +37,7 @@ Freebuff 提供经过筛选的模型目录。常规模型选择器目前包括
 | **MiMo 2.6 Flash**          | 完整和受限访问 | 所有模式下的默认模型；均衡性能并支持图像         |
 | **GLM 5.3 Flash**           | 完整和受限访问 | 推理最深入，不消耗会话                           |
 | **DeepSeek V4.1 Flash** | 完整和受限访问 | 快速编程和工具调用，不消耗会话                   |
+| **DeepSeek V4.1 Flash Fast** | 完整访问   | 快速模式：同一模型运行于 DeepSeek 官方 API，将工作拆分给并行子智能体并自行验证结果；按 DeepSeek 的高峰和非高峰时段定价 |
 | **GPT-6 Luna**              | 完整访问       | 综合能力强，原生支持图像；运行于 OpenAI flex 容量 |
 | **MiMo 2.6 Pro**            | 完整访问       | 小米更强的推理模型，支持图像 |
 | **Solar Mini 4**            | 完整和受限访问 | Upstage 的快速轻量模型；52.4 万上下文，仅支持文本 |
 
@@ -141,6 +141,8 @@ test.each([
     useFreebuffModelStore.getState().setSelectedModel(id)
     const setup = await renderSelector(40, undefined, 100, now)
     expect(setup.captureCharFrame()).toMatch(new RegExp(`│ +${before} Freebucks/hr`))
+    // At peak, line 2 says when the off-peak price is back.
+    expect(setup.captureCharFrame().includes('10 Freebucks/hr from')).toBe(before === 15)
     expect(setup.captureCharFrame()).not.toContain('Off-peak')
     expect(setup.captureCharFrame()).not.toContain('normally 15/hr')
     expect(setup.captureCharFrame()).not.toContain('Server fallback price notice')
@@ -151,6 +153,7 @@ test.each([
     })
     await setup.renderOnce()
     expect(setup.captureCharFrame()).toMatch(new RegExp(`│ +${after} Freebucks/hr`))
+    expect(setup.captureCharFrame().includes('10 Freebucks/hr from')).toBe(after === 15)
     expect(setup.captureCharFrame()).not.toContain('Off-peak')
     expect(setup.captureCharFrame()).not.toContain('normally 15/hr')
   } finally {
 
@@ -1,3 +1,4 @@
+import { freebucksOffPeakCopy } from '@codebuff/common/util/freebuff-off-peak-price'
 import { isFreebucksPeakModel } from '@codebuff/common/util/freebuff-peak-price'
 import { watchFreebucksPriceChanges } from '@codebuff/common/util/freebuff-price-changes'
 import { freebucksListPriceFor } from '@codebuff/common/util/freebuff-price-order'
@@ -516,6 +517,15 @@ export const FreebuffModelSelector: React.FC<FreebuffModelSelectorProps> = ({
           warn: (freebucks?.balance ?? 0) < rowPrice,
           highlight: freebucksListPriceFor(freebucks, model.id) !== undefined,
         })
+        // At peak, when the off-peak price is back, so a user can wait for it.
+        // On the clock `freebucks` was resolved with, not `now`, which can lag.
+        const resumes = freebucksOffPeakCopy(freebucks, model.id)?.resumes
+        if (resumes) {
+          details.push({
+            text: `${freebucksPriceLabel(resumes.price)} from ${resumes.at}`,
+            warn: false,
+          })
+        }
       }
       // Beside the price it qualifies, in the warning colour. The terminal has
       // no tooltip to hold the catalog's full sentence, so the row carries its
 
@@ -17,7 +17,8 @@ import {
   resolveFreebuffWebModelForLimitedTier,
   FREEBUFF_GEMINI_38_FLASH_MODEL_ID,
   FREEBUFF_MIMO_V26_PRO_MODEL_ID,
-  FREEBUFF_ENABLE_FAST_MODE_IN_UI,
+  FREEBUFF_FULL_ACCESS_ONLY_MODEL_IDS,
+  isFreebuffModelAllowedForAccessTier,
 } from '../freebuff-models'
 import {
   FREEBUFF_SUBSCRIPTION_MODEL_IDS,
@@ -160,15 +161,12 @@ describe('paid plans at limited access', () => {
     // Pinned so that adding a row to a plan is a decision somebody states
     // here, not a diff that passes quietly.
     // MiMo 2.6 Pro joined on 2026-09-21, on Luna's terms (plan-only at
-    // limited access, Freebucks at full). DeepSeek Flash fast mode joined on
-    // 2026-09-26 on the same terms; Muse Spark 1.3 joined on 2026-09-28,
+    // limited access, Freebucks at full). Muse Spark 1.3 joined on 2026-09-28,
     // paid-only on every surface, and GPT-6.1 Sol on 2026-09-29 on the same
     // terms. Kimi K3 (CrofAI) left on 2026-10-01: its provider is retired and
-    // no picker lists it.
-    // The fast row joins the plan with its picker row, behind the UI switch.
-    expect(FREEBUFF_SUBSCRIPTION_MODEL_IDS).toHaveLength(
-      FREEBUFF_ENABLE_FAST_MODE_IN_UI ? 8 : 7,
-    )
+    // no picker lists it. DeepSeek Flash fast mode is NOT a plan model: it is
+    // full access only (see the test below).
+    expect(FREEBUFF_SUBSCRIPTION_MODEL_IDS).toHaveLength(7)
   })
 
   test('a limited-tier plan-only row is never free at limited access', () => {
@@ -188,6 +186,42 @@ describe('paid plans at limited access', () => {
     expect(FREEBUFF_LIMITED_TIER_PLAN_ONLY_MODEL_IDS.length).toBeGreaterThan(0)
   })
 
+  test('a full-access-only row is open at full access and absent at limited access, plan or not', () => {
+    expect(FREEBUFF_FULL_ACCESS_ONLY_MODEL_IDS.length).toBeGreaterThan(0)
+    for (const model of FREEBUFF_FULL_ACCESS_ONLY_MODEL_IDS) {
+      for (const paid of [false, true]) {
+        expect(
+          isFreebuffSessionModelAllowedForAccessTier(model, 'full', paid),
+        ).toBe(true)
+        expect(isFreebuffModelAllowedForAccessTier(model, 'full', paid)).toBe(
+          true,
+        )
+        expect(
+          getFreebuffModelsForAccessTier('full', paid).map((m) => m.id),
+        ).toContain(model)
+
+        expect(
+          isFreebuffSessionModelAllowedForAccessTier(model, 'limited', paid),
+        ).toBe(false)
+        expect(
+          isFreebuffModelAllowedForAccessTier(model, 'limited', paid),
+        ).toBe(false)
+        expect(isFreebuffWebModelAllowedForLimitedTier(model, paid)).toBe(false)
+        expect(
+          resolveFreebuffSessionModelForAccessTier(model, 'limited', {
+            hasPaidSubscription: paid,
+          }),
+        ).toBe(LIMITED_FREEBUFF_MODEL_ID)
+        expect(
+          getFreebuffModelsForAccessTier('limited', paid).map((m) => m.id),
+        ).not.toContain(model)
+      }
+      // Not listed locked at limited access either: a plan cannot unlock it.
+      expect(FREEBUFF_LIMITED_TIER_PLAN_ONLY_MODEL_IDS).not.toContain(model)
+      expect(FREEBUFF_SUBSCRIPTION_MODEL_IDS).not.toContain(model)
+    }
+  })
+
   test('every plan model resolves in the Web catalog', () => {
     // The plans page renders the plan lineup via getFreebuffWebModel, which
     // FALLS BACK to MiMo 2.5 for an id the Web catalog lacks — it would
 
@@ -1138,14 +1138,14 @@ export const MUSE_SPARK_FALLBACK_NOTICE =
  *  wired even when these models are hidden from the Freebuff picker. */
 export const FREEBUFF_ENABLE_MIMO_MODELS_IN_UI = true
 /** UI-only rollout switch for the DeepSeek Flash FAST MODE row
- *  (`deepseek/deepseek-v4-flash-fast`). Off: no picker on any surface lists
- *  the row (the CLI, Web and Desktop pickers read FREEBUFF_MODELS; the iOS and
- *  Android catalogs carry the same switch by hand), while everything behind it
- *  stays wired — the id is SUPPORTED and admitted, priced on DeepSeek's clock, routed
- *  to DeepSeek direct alone, and runs the base3-fast harness — so a client
- *  that sends the id gets the real thing. Flip to true to ship the row; the
- *  tests that count picker rows follow this switch. */
-export const FREEBUFF_ENABLE_FAST_MODE_IN_UI = false
+ *  (`deepseek/deepseek-v4-flash-fast`). On since 2026-10-04, for full access
+ *  only (FREEBUFF_FULL_ACCESS_ONLY_MODEL_IDS). Off: no picker on any surface
+ *  lists the row (the CLI, Web and Desktop pickers read FREEBUFF_MODELS; the
+ *  iOS and Android catalogs list it by hand), while everything behind it stays
+ *  wired — the id is SUPPORTED and admitted at full access, priced on
+ *  DeepSeek's clock, routed to DeepSeek direct alone, and runs the base3-fast
+ *  harness. The tests that count picker rows follow this switch. */
+export const FREEBUFF_ENABLE_FAST_MODE_IN_UI = true
 /** UI-only rollout switch for the streak indicator in the waiting room. */
 export const FREEBUFF_ENABLE_STREAK_IN_UI = true
 /** Local/debug switch: force the localhost free-mode country bypass into
@@ -1747,16 +1747,17 @@ const DEEPSEEK_V4_FLASH_MODEL = {
  *    from that grant at admission and runs a single direct lane in the router
  *    (web/src/llm-api/deepseek-router.ts).
  *
- * Priced on DeepSeek's own clock (freebuff-freebucks.ts): 45 Freebucks in
+ * Priced on DeepSeek's own clock (freebuff-freebucks.ts): 50 Freebucks in
  * the weekday window where DeepSeek direct doubles, 25 the rest of the time.
  * The harness spends about 1.3x base3 per task, and DeepSeek direct bills
  * 1.7x Luminal off-peak and 3.4x at peak on the same tokens.
  *
  * Everything else tracks the Flash row on purpose — the same DeepSeek data-use
  * terms, the same effort ladder, and `multimodal: true` because the direct
- * lane is the one lane that reads images. Premium and plan-only at limited
- * access, on MiMo 2.6 Pro's terms: open to every full-access account, metered
- * in Freebucks at its own price.
+ * lane is the one lane that reads images. Full access only
+ * (FREEBUFF_FULL_ACCESS_ONLY_MODEL_IDS): open to every full-access account on
+ * any plan, metered in Freebucks at its own price, and not offered at limited
+ * access even with a plan.
  */
 const DEEPSEEK_V4_FLASH_FAST_MODEL = {
   id: FREEBUFF_DEEPSEEK_V4_FLASH_FAST_MODEL_ID,
@@ -3061,9 +3062,9 @@ export const FREEBUFF_MODELS = [
   GLM_V53_FLASH_MODEL,
   DEEPSEEK_V4_FLASH_MODEL,
   // FAST MODE beside the row it is a variant of (2026-09-26), behind
-  // FREEBUFF_ENABLE_FAST_MODE_IN_UI until it ships. Order here only matters
+  // FREEBUFF_ENABLE_FAST_MODE_IN_UI. Order here only matters
   // off the meter: every picker sorts its rows cheapest first once prices
-  // arrive, and at 25-45 Freebucks this lands among the premium rows.
+  // arrive, and at 25-50 Freebucks this lands among the premium rows.
   ...(FREEBUFF_ENABLE_FAST_MODE_IN_UI ? [DEEPSEEK_V4_FLASH_FAST_MODEL] : []),
   // GPT-6 LUNA TAKES 5.6'S SLOT (2026-09-22). Same position, same tagline,
   // half the price on the flex lane; 5.6 left this list in the same change and
@@ -4247,12 +4248,8 @@ export const FREEBUFF_LIMITED_TIER_PLAN_ONLY_MODEL_IDS: readonly string[] =
   Object.freeze([
     FREEBUFF_GPT_6_LUNA_MODEL_ID,
     FREEBUFF_MIMO_V26_PRO_MODEL_ID,
-    // Flash FAST MODE (2026-09-26), on MiMo 2.6 Pro's terms: three times the
-    // Flash price, so plan-only where the free pool is 25 a day. Behind the
-    // UI switch with the picker row: a plan cannot sell what no picker lists.
-    ...(FREEBUFF_ENABLE_FAST_MODE_IN_UI
-      ? [FREEBUFF_DEEPSEEK_V4_FLASH_FAST_MODEL_ID]
-      : []),
+    // Flash fast mode is not here: it is not offered at limited access at all
+    // (FREEBUFF_FULL_ACCESS_ONLY_MODEL_IDS).
     // Muse Spark 1.2 is excluded: it is not offered at limited access at all
     // (not even with a plan), only kept for released binaries at full access.
     ...FREEBUFF_PRO_ONLY_CATALOG_MODEL_IDS.filter(
@@ -4264,6 +4261,22 @@ export function isFreebuffLimitedTierPlanOnlyModelId(id: string): boolean {
   return FREEBUFF_LIMITED_TIER_PLAN_ONLY_MODEL_IDS.includes(id)
 }
 
+/**
+ * Rows offered at FULL access only, on any plan or none. A limited-tier
+ * account does not see them, locked or otherwise, and a plan does not unlock
+ * them there, so they stay out of the geo-exempt set, the limited plan-only
+ * set and the plan-metered set alike.
+ *
+ * Flash fast mode (2026-10-04): a fan-out on DeepSeek direct at 25-50
+ * Freebucks an hour, which the limited tier's pool cannot carry.
+ */
+export const FREEBUFF_FULL_ACCESS_ONLY_MODEL_IDS: readonly string[] =
+  Object.freeze([FREEBUFF_DEEPSEEK_V4_FLASH_FAST_MODEL_ID])
+
+export function isFreebuffFullAccessOnlyModelId(id: string): boolean {
+  return FREEBUFF_FULL_ACCESS_ONLY_MODEL_IDS.includes(id)
+}
+
 export const FREEBUFF_WEB_GEO_EXEMPT_MODEL_IDS: readonly string[] = [
   ...new Set<string>([
     ...LIMITED_FREEBUFF_MODEL_IDS,
@@ -4274,7 +4287,8 @@ export const FREEBUFF_WEB_GEO_EXEMPT_MODEL_IDS: readonly string[] = [
         // This is deliberately broader than the global Pro set. Luna is free
         // from the premium pool at full access but still plan-locked here;
         // Gemini 3.8 Flash is plan-only at every tier.
-        !isFreebuffLimitedTierPlanOnlyModelId(model.id),
+        !isFreebuffLimitedTierPlanOnlyModelId(model.id) &&
+        !isFreebuffFullAccessOnlyModelId(model.id),
     ).map((model) => model.id),
   ]),
 ]
@@ -4557,12 +4571,10 @@ export const FREEBUFF_PLAN_METERED_CATALOG_MODEL_IDS: readonly string[] =
     // With Luna: this list is what widens the limited tier for a subscriber,
     // so a plan-only row missing here would be offered and then coerced away.
     FREEBUFF_MIMO_V26_PRO_MODEL_ID,
-    // Flash fast mode (2026-09-26), for the same reason as MiMo 2.6 Pro —
-    // and, like the picker row, only once FREEBUFF_ENABLE_FAST_MODE_IN_UI is
-    // on: a plan can only cover a model a picker offers.
-    ...(FREEBUFF_ENABLE_FAST_MODE_IN_UI
-      ? [FREEBUFF_DEEPSEEK_V4_FLASH_FAST_MODEL_ID]
-      : []),
+    // Flash fast mode is not here: this list is what widens the limited tier
+    // for a subscriber, and fast mode is full access only
+    // (FREEBUFF_FULL_ACCESS_ONLY_MODEL_IDS). A full-access subscriber pays for
+    // it in Freebucks like everyone else at full access.
     // Muse Spark 1.3 (2026-09-28): the plans page promises every plan model in
     // every country, so a limited-region subscriber must be able to open it.
     // (1.2 is deliberately absent: it survives only for released binaries at
 
@@ -81,4 +81,50 @@ test('does not label a stale regular-price quote as discounted', () => {
   )!
   expect(copy.active).toBe(false)
   expect(copy.tooltip).toContain('10 Freebucks/hour')
+  // The policy says off-peak, so the next change is the window's END: no
+  // promise of a drop then.
+  expect(copy.resumes).toBeUndefined()
+})
+
+test('at peak, says when the off-peak price is back, with the weekday when it is not today', () => {
+  // DeepSeek's clock: off-peak 10:00-00:00 UTC daily and all Beijing weekend.
+  const fast = {
+    prices: { fast: 50 },
+    offPeak: {
+      fast: {
+        startHourUtc: 10,
+        endHourUtc: 0,
+        weekendsOffPeak: true,
+        price: 25,
+        regularPrice: 50,
+      },
+    },
+  }
+  // Monday 01:00 UTC is Sunday 6 PM in Los Angeles; the drop is Monday there.
+  const sunday = freebucksOffPeakCopy(fast, 'fast', {
+    now: Date.parse('2026-10-05T01:00:00Z'),
+    timeZone: 'America/Los_Angeles',
+  })!
+  expect(sunday.resumes).toEqual({ price: 25, at: 'Mon 3:00 AM PDT' })
+  expect(sunday.tooltip).toStartWith(
+    'Back to 25 Freebucks/hour at Mon 3:00 AM PDT. Off-peak: 25 Freebucks/hour, daily',
+  )
+  // Same local day: the time alone.
+  expect(
+    freebucksOffPeakCopy(fast, 'fast', {
+      now: Date.parse('2026-10-05T08:00:00Z'),
+      timeZone: 'America/Los_Angeles',
+    })!.resumes,
+  ).toEqual({ price: 25, at: '3:00 AM PDT' })
+  // Off-peak: nothing to wait for.
+  const offPeak = freebucksOffPeakCopy(
+    { ...fast, prices: { fast: 25 } },
+    'fast',
+    {
+      now: Date.parse('2026-10-05T12:00:00Z'),
+      timeZone: 'America/Los_Angeles',
+    },
+  )!
+  expect(offPeak.resumes).toBeUndefined()
+  expect(offPeak.tooltip).toStartWith('Off-peak:')
 })
@@ -18,7 +18,7 @@ export function freebucksOffPeakCopy(
   const offer = info?.offPeak?.[modelId]
   if (!offer || info?.prices[modelId] === undefined) return undefined
 
-  const { start, end } = offPeakPriceAt(offer, now)
+  const { start, end, nextChangeAt, price } = offPeakPriceAt(offer, now)
   const zone = resolveWindowTimeZone(timeZone)
   const fmt = new Intl.DateTimeFormat(undefined, {
     hour: 'numeric',
@@ -33,13 +33,35 @@ export function freebucksOffPeakCopy(
     : ''
   // The resolved quote owns the badge too; do not run a second pricing clock.
   const active = info.prices[modelId] === offer.price
+  // At peak, when the off-peak price is back, so a reader can choose to wait.
+  // Only when the policy agrees it is peak: a stale quote must not promise a
+  // drop at what is really the END of the off-peak window.
+  const resumes =
+    !active && price !== offer.price
+      ? { price: offer.price, at: formatResumeAt(nextChangeAt, now, zone) }
+      : undefined
   return {
     active,
     badge: 'Off-peak',
-    tooltip: `Off-peak: ${offer.price} Freebucks/hour, daily ${hours}${weekend}.`,
+    resumes,
+    tooltip: `${resumes ? `Back to ${resumes.price} Freebucks/hour at ${resumes.at}. ` : ''}Off-peak: ${offer.price} Freebucks/hour, daily ${hours}${weekend}.`,
   }
 }
 
+/** "3:00 AM PDT" when `at` falls on the reader's today, "Mon 3:00 AM PDT"
+ *  otherwise: a peak ending after local midnight must not read as tonight. */
+function formatResumeAt(at: number, now: number, zone: string) {
+  const day = new Intl.DateTimeFormat('en-CA', { timeZone: zone })
+  const today = day.format(at) === day.format(now)
+  const time = new Intl.DateTimeFormat(undefined, {
+    ...(today ? {} : { weekday: 'short' as const }),
+    hour: 'numeric',
+    minute: '2-digit',
+    timeZone: zone,
+  }).format(at)
+  return `${time} ${formatWindowTimeZoneLabel(new Date(at), zone)}`
+}
+
 /** The weekend a policy with `weekendsOffPeak` means — Friday 16:00 to Sunday
  *  16:00 UTC, Saturday and Sunday in Beijing — as the reader's own clock shows
  *  it, taken from the most recent such weekend so seasonal time applies. */