I'd contact them and ask them to send you a confirmation of your stats history for the time period listed on those checks. If it doesn't jive, let them know - better to be honest and know that for every opportunity you left behind there are 4 other better ones for you
Did you check if you signed up a whale under you and that may be why you're getting paid? Also, I'd check the stats for the exact dates that it gives - sometimes during bonus periods, the only way you'll see that bonus payout is if you go to those dates exactly.