If you remove the outlaying scores, and consistently put in scores that push you up, or pull you down, that's your grade. Fudging it so you only go up is just fudging it.
I'd also add, that all scores from every league should be added, and if a competitor doesn't hand in score card, they lose trophy and qualification results from that league. Removing outlaying scores accounts for the extremely rare event of non pilot induced kit mishap.
BFTA/NSRA County Coach
CSFTA Chairman/BFTA Rep