I tried to do further analysis to see which affects per-sector rating (and thus bonus exp), Favor, Retrieval, or both. But, I'm running into the issue where all the stats are loosely correlated with each other. A ship with higher Favor often also has higher Retrieval, and vice versa. There's a clear correlation between higher favor and higher ratings. The data suggests that retrieval might also correlate with higher ratings, but that is less clear. Trying to isolate a variable by, say, only looking at the retrieval ratings of ships with exactly 80 favor is running into an issue where the vast majority of ships with 80 favor also have 80 retrieval. So, there aren't enough datapoints with the same retrieval value other than 80 and exactly 80 favor to compare it to the 80/80 set.

So, I have no idea...