OK, I've done that and all is well, including auto import.
Another question.
Background: I've set my rules for 6-max, run Rate Players for 6-max tables only and have all my rules in place. I now decide to switch to full ring (which I played for all of 2009 but not in 2010) . I export my 6max rules as a backup, rewrite my rulesets to apply to FR tables, untick all the 6-max boxes and tick all the FR ones in auto rate config, and set the auto rate start date to 1/1/2009. I set my HUD with player ranges 2-6 and 7-10. I then sit at a FR table without running Rate Players. At that table is a player against whom I played often at FR during 2009. He doesn't have an icon because I've only run Rate Players for hands from 6max tables.
The question is, when auto rate imports that player's first hand, will it also find the hands I played against him during 2009 and rate him accordingly, or will it treat that hand as Hand 1? And, if I'd played both FR and 6max against that player (in which case he'd have an icon from my previous 6Max Rate Players), would it (re)rate him on just his FR hands (given that I unticked all the 6max boxes in auto rate config above)?
If it treats his first hand as Hand 1, and/or doesn't re-rate, then I suppose I'll have to run Rate Players again, and re-run it every time I switch from 6max to FR or vice versa (to ensure that any player against whom I have hands at both 6max and FR is correctly rated).