CS claims if your prestige is a B in RS1 and goes up to an A in RS2 and you send all your HVs in RS2 then your HVs are calculated with the A prestige.
However, I've gone after multiple recruits with zero preferences and based on the recruiting effort I compared with the coach I battled that explanation does not make sense. Most notably there was a kid I was ahead about 200 APs on, the other coach had a higher B than I did in RS1 and I went to B+ in RS2 and he went to B-. We sent all effort (starts, minutes, max HV, CV) in RS2 and despite me having more APs I had the lower % to sign the kid. The only way that's possible is if the effort was calculated with the RS1 prestige.
Similarly, I believe it was the Uconn coach in Knight about 15 seasons back that was "very good" for wants rebuild in RS1 at a C prestige, he went to the title game and became A- (maybe B+) and was still "very good" for wants rebuild in RS2.
Other coaches have posted similar stories so either the system is glitchy or effort and preferences are based off RS1.