Wage reporting when hours change weekly - any advice?

I work some days through a staffing agency while still certifying. This is my first time dealing with any of this. Pay posts on a different day from when I work. Did anyone get an overpayment notice from a mistake?

The claimant handbook has worked examples for part-time pay. Mine was clearer than the phone line.

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