So on average and across the entire meta game, 2 A-wings do slightly more damage than one ship with 3 attack dice. This is before considering the effect of the white K-turn on the Defender's action economy.
I'm assuming your values take some kind of consideration for number of green dice defenders (not Defender) will roll? Because 2 attack ships x 2 also means double the number of agility dice rolled when comparing to a single 3 attack ship. So for example, a TIE Defender will have a much easier time putting damage through the a-wing's 3 green dice than they will have trying to put damage through its 3 green dice (for example).
Edited by blade_mercurial