Well, I'm not real clear on how that whole 'sliding scale' for perk point costs goes, I suppose it is possible that when you took off it was worth 200 points, but when you landed it was only worth 130 (due to changing numbers) so you lost points that way?
As far as the P-51 goes, you are never going to rack up any significant perk points in it. It has a ENY value of 10, so unless you kill a perk plane, you are only going to get 1 perk per kill, tops. Typically, it will be less than that. I've got no idea what you killed, but lets say your side has a perk modifier of 1.2, and you kill 6 202s in a P-51D. Well, 10/60 = .16 perks per kill. .16x6= 1. 1x1.2= 1.2 perks, for 6 kills. And that is assuming none of them were proxy kills, which happens quite often. A proxy kill, in case you didn't know, does not give you any perks. On the other hand, just to give you a different example, lets say you are in a 202 and manage to kill 6 P-51Ds. 60/10= 6. 6x6=36, 36x1.2= 43.2 perks. There is another modifier for landing them, I think it is 1.25, but it might have changed.
