Sorry to nitpick, but Payback couldn't possibly work that way. Payback doesn't care what the target did as long as it has already done something during the turn.what has to be said first, in a double battle, revenge, avalanche, payback etc., moves which are affected by how the foe "behaves" get their boost only if the pkmn that is targeted by your attack activates your boost
Good info about Revenge and Avalanche, though.