The displaying credits in the top right are multiplied I think, in the same way the team attack is. I suppose it sort of indicates the doubled exp gain, or something. But I'm pretty sure that if you shoot down a scout for 30 credits, the top left will show alot more than 30 credits.
Ships have 2 sources of AAW for their natural AA gun. Their sailors and the ship. The sailor AAW stat is disabled, it doesnt have a reduced impact, it has no impact whatsoever. A ships AAW stat is what it is, I'm pretty sure the AAW stat isnt increased by anything in WaW. And each ship has its own base AAW value, like the Dunk has 264, which is a fair amount.
Next time you're in WaW, watch for what your ship shoots down naturally. You might shoot down a scout worth 30 credits, but the top right might display 1200 or something. I noticed quite a few games where Ive earned 3k+ credits without even having AA guns, and I'm pretty sure I'd notice shooting down 100 scouts or 20 fighters with my ships natural AA.