Wage reporting when hours change weekly after 10 years as an insurance claims processor

I picked up part-time shifts as an insurance claims processor and I am confused about how to report them. It has been weighing on me all week. The form asks for gross earnings, which I do not see until later.

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

Keep everything in writing and save the confirmation numbers. It saved me later.