A few points that might help. I have found that there are discrepancies between check stub and RRC reports, but be sure to go to the disposition pages to see what they sold, vs what was produced. Some companies use the production on the lease, etc. So, try tying the amounts you are paid for with the disposition amounts.
Secondly, the negatives appear, usually when they reprice gas (operators are supposed to pay within a certain amount of time, and they estimate the price of gas). I have seen stubs that showed the same amounts in and out with slightly different prices, going both positive and negative. If you see a negative and no similar amounts, try a previous stub.