This is most likely because it doesnt account for splashers overriding allied paint within 3 blocks, not sqrt(2). https://releases.battlecode.org/client/battlecode25/2.0.2/index.html?gameSource=https%3A%2F%2Fstorage.googleapis.com%2Fmitbattlecode-production-secure%2Fepisode%2Fbc25java%2Freplays%2F1722a0aa-8a98-4175-bd8a-b679f50ae723.bc25java&page=Game Round 493, (28,22)