Are you suggesting that we're getting screwed according to the types of missions that are available for players to run or by the returns on the missions?
What I can say definitively from the data I have is that your first point is correct. There is a systematic bias that makes certain missions more likely to be selected than other missions. Your second point is the issue I cannot answer because of the stats I no longer remember well enough. I cannot say yes or no to it, because the answer to that question is mixed up with what creates the first question you raised. In statistical testing, that is something known as an interaction effect. Detecting statistically meaningful interaction effects requires a bit of "finesse", something I can't quite provide. But because I know the interaction is there, I'm keeping my mouth shut about what the biases are. It's as if my car won't start because it seems that no gas is getting to the engine. I might think there is no gas in the tank, but it could also be that the fuel pump is broken or the fuel line is clogged. Rather than saying the right thing for the wrong reason, I'd rather wait until all the reasons are understood. Speaking out right now could just make a bigger mess of things.