Reporting part-time earnings while on benefits after 10 years as a quality inspector

I picked up part-time shifts as a quality inspector and I am confused about how to report them. I have read a lot of threads here and could not find my exact situation. The form asks for gross earnings, which I do not see until later. Did anyone get an overpayment notice from a mistake?

I estimated and then checked my pay stub. When there was a small difference I wrote to the agency to correct it.