There are times when I flew 40 hrs in a month and got 95 hrs pay. There was one month on reserve I got 75 hrs pay and flew 2.6 hrs. some months I get paid for 90hrs and fly 80 due to cancellations and under block. It just depends on the the contract. Most airlines are going to have a minimum garuantee, in this case 75. You are gauranteed to get paid that. There are times when it can go lower. Like calling in sick and not electing to use sick time. Trading or dropping days below 75.