If you are a health and human service case worker, could you answer this question?

Last yr, when I applied for SNAP Benefits, my fiance was making about 2080 before taxes and about 1600 after. Now he makes about the same amount, BUT he has been getting like an extra hr of over time each month. So now he makes about 1800 after. Because of this small change, they have cut how much we recieve by over half. As I said before, he really only gets like an extra hr of over time, but it's nothing dramatic. My question is why has our benefits been cut so dramatically. I have asked my local office and they keep seeing they use the gross pay and I understand that but just because they do that does not mean that our benefits should have decreased that much. She also told me that just bc we pay 600 a dollars per month utilities that the only standard excess deduction we get is 69. I am just so confused about the entire process. I don't understand how we could have gotten a certain amount in the beginning and now bc he gets a little bit extra OT, the amount decreased. We also have a 7 month old baby in the household whereas in the beginning we did not, (was still preg. w/ him obviously). I just know that there has to be something wrong about how the info. was entered in bc it is no way a few hrs. could have caused our benefits to drastically decrease.