Confusing Research Rewards

Since the Sons of Attila update came out, I’ve been noticing that my research gain has been quite inconsistent, and lower than I expect. I checked the wiki page on the update and didn’t find any information on what might be causing this, so I’d like to know if anyone else is having the same problem.

I’m currently playing 10.7 Germany in Air RB, for the most part the F4F. This isn’t caused by research efficiency as I am researching the MiG-23 which is also in rank VII. As an example, if I get, say, 2 kills in a game - so about 1200 points - I can generally expect 2000-3000 research as a reward. Meanwhile, in one match I scored ~3000 points, then received a similar number of RP after the battle ended. Both of these examples assume a victory for my team. This is particularly odd because shortly after the update came out I was getting up to 6000 RP each game, but now it’s gone down.

My primary confusion I suppose is why there appear to be diminishing returns from scoring more points, and why in some cases I get less RP than I did score, despite the plane having a 2.3x multiplier to research.