Grade Inflation

We (Drake U. Pharmacy) began using TBL last year in one of our major courses (Therapeutics, a 3-semester course, 110 students) - this year is our 2nd year. Grades this Spring semester were quite high - 91% average (85 A final course grades). This spring semester included 4 exams (70% of course grade), 9 IRATs (10% of course grade), 9 GRATs (15% of course grade), and 2 peer evaluations (5% of course grade). Many students received an A or B that actually had exam and IRAT averages each less than the final grade (ie, exam and IRAT av. 75% but B grade or even 77% each av. and A final grade) - the high GRAT and peer evals pushed up final averages, perhaps too much. My questions: how much should group work/peer evals factor into final grades, and have others had a similar experience (ie, where individual, group, and final course grades do not seem to correlate)?