A8's best speed alt is 20k. You go higher and power just drops off like mad.
IF you're going to fly a 190 at alt, consider your weapons loadout. WGrs are a no-no. They cause massive drag, lots of weight, and reduce climb like crazy. Even 20/30mm outboard guns add a lot of weight and reduce climb significantly.
That's the problem. If you're going up there you need the minimum guns package, but that means you don't get the benefit of the A-8 (all the guns) against the bombers.
Further, it's a dog at alt. You will stall out and lose altitude with a minimum of movement because you don't have enough excess speed. Somebody did a test and found that the 190a8 can only do about 1.5G turns without losing alt, while US planes like the p51 and p47 can do 2.5-3G turns without losing alt. You're screwed if you are in a dogfight.
However, the bombers were down by 15k or so I think (by my area, I was one of their escorts) so if you DO have this excess speed you can dive down on them. Even descending down to 18k (from 25k) you increase your chances of surviving against escorts a great deal, because the air is thicker and your wings more effective and the gap between IAS/TAS is smaller
Long story short: You're that high to bounce bombers. You're ONLY that high so that the bombers are below you when you find them. If you run into bad guys, RUN AWAY. 190A8 bomber busters needed their own escorts historically, and you will too.
