I’d need to play more ground to make confident statements specifically to ground RB/ground SB.
Best bet is to screenshot the scoreboard tooltip when you hover over your score breakdown (and total score gained) just before a match ends. Then in the e-mail post-battle summary, look at per-vehicle score, activity%, RP and SL rewards and collect these into a spreadsheet over a sufficiently large number of games.
For this though, I do concur with @Creastroy and Sternlos -
If we are talking in Air RB or Air SB - the time you obtain score is inconsequential for your final activity% - what matters is how long you spent alive. Activity%, and thus the bulk of RP gained, seems to be a function of the amount of score players earn for a given length of time alive per -
In SB, we have it down to a pretty exact science for what score quantities correspond to what activity% for a single life:
For every 15 minute units of scoring, after which score earned is treated as starting from 0 for the next cycle -
200 points = 54% reward
400 points = 75% reward
600 points = 86% reward
800 points = 90% reward
1050+ points = 92% reward (after which it plateus - 2650 still gave same score as 1050 in my own experience)
(obtained from the following dataset: HeliBoys Sim EC Sheet - Google Spreadsheets)
Due to lack of fixed scoring periods in air RB to reduce it to simple f(score) function, we only have very loose data:
Spoiler
which gave birth to the following qualitative diagram that tries to represent f(score, time alive):
Spoiler
For ground RB, due to the complexity on top of the difficulties in ARB, we don’t even have conceptual diagrams due to respawns complicating things significantly (especially if we consider that dying awards score - does this score increase activity of last life, or does it improve activity on respawn too? What about an assist or kill that’s scored after you died and are in a new vehicle? In ASB, dying clearly improves past life score while assists/kills after respawns improve your reward for next life (as long as you respawn in the same vehicle, I’d need to test if I respawned in another vehicle to make a statement more broadly)).
One thing I also observed, hence “screenshot the tooltip” is that some sources of score don’t get recorded in the post-battle e-mail report for individual vehicle breakdown. Whether that means that score is treated as a carry-over activity or just gaijin things is beyond me.