Well, it appears to work for me. I used this setting:
(setq gnus-parameters
'(("regressions.*"
(gnus-use-adaptive-scoring nil))
("general-personal.*"
(gnus-use-adaptive-scoring t))))
Perhaps your regexps don't match your group names? The above regexps will match groups that look like mail. and gmane. (the . being a real period).
The way I tested it was to enter each of the two groups and did an eval on the variable M-: gnus-use-adaptive-scoring RET - though you could also just do help on the variable C-h v gnus-use-adaptive-scoring RET.
Perhaps what you want is not to turn adaptive-scoring off, but just to turn scoring off. AFAIK, adaptive-scoring is Gnus trying to figure out scoring for the articles, but not the actual use of scoring.
So maybe this does what you want?
(setq gnus-parameters
'(("mail\\..*"
(gnus-use-scoring nil))
("gmane\\..*"
(gnus-use-scoring t))))