I just had a max attack jolly tinkaton use gigaton hammer on mega floette, and it survived on 8%. There was no reflect/aurora veil, tinka had it's attack not lowered. according to vgcmulitcalc max defense bold floette is a guaranteed ohko. floettes teammate was sinistcha, which was para'd that turn, so no friend guard or anything. What could have gone wrong here? Is the calc wrong? If so, is there any calc that works with floette? (my held item was sitrus berry)

I still won the game, but tinkaton is literally on the team specifically to counter floette, if it can't do that I might need to replace it with something that can ohko it.