Another thing to consider might be the victory condition for the Luftwaffe.
The 8th AF time-frame depicted in the Combat Tour, is a part of a bigger war. If it is like anything I'm imagining, where the CT is a mission-oriented, realistic role-playing game which flow of action is more coherent with real-life, then the 109s in their escort role and the 190s in the intercept role, do not necessarily have to engage the US forces to shoot them all down.
IIRC, typically a 10% loss inflicted to a mass bomber stream would be considered an "unacceptably high loss" for the USAAF. If a mission spawns with 100 bombers inbound with 32 US escorts, the Luftwaffe counteraction would probably spawn with multiple interception attempts all along the way.
Something like 8x 109s and 16x 190s will hit the bomber stream for no more than 15 minutes, where the 190s may get perhaps one or two passes into the bomber stream and shoot maybe 2~3 of the bombers down. Then this mission expires, and the 109s and 190s will run low and home. The escorts will not be able to follow them, since they are given a duty as close escort, and after some time, another squadron of the LW will merge with the bomber stream and attempt another interception.
It's not as if the 109s and 190s will be given a mission order to shoot all 100 buffs and 32 escorts down. Naturally, knowing the disadvantages in the high-alt theater, the 109 and 190 pilots will do all they can to make the interception attempt as short as possible, chipping off only one side of the bomber stream with 3~4 buffs, and then turning back and disengaging as soon as possible to avoid the onslaught from the US planes. Multiple "chipping" will happen with multiple attempts by multiple teams, and if the LW can bring down something like 20 of those 100 buffs, then the whole mission is a success. The 32 US escorts may not have lost a single P-51 or a P-47 and yet, they still lose.
The CT is not the MA. It's not the realm where win/loss is determined by which planes you've individually shot down. Each side is given a duty to accomplish the mission, and no matter how flashy and skilled you are, if your side fails the mission then its over.