You're right, but remember that along with BP, there's also accuracy to take into account. 80% accuracy means it only will be a 2HKO 64% of the time, so it isn't exactly reliable. I think that CAP6 can have Stone Edge and Ice Punch and still be countered or at least checked by several pokémon, like Slowbro, Cresselia, Starmie, Zapdos and Celebi, among others. Togekiss, too.Well BP of a move make up much of the bulk when determine how much damage a Pokemon delivers/receives. With Ice Punch, it would have to run Adamant, max attack, and Life Orb just to 2HKO with SR up. Now with Stone Edge, it could only need 108 attack netural natured to gain a 2HKO from the bird. Stone Edge would make really hard for Zapdos to counter it, thought it still make a strong check.
By the way, congratulations on your victory :) CAP6 has a really good spread.