How do you report hours that vary week to week? - any advice?

My hours change every week at my new part-time job and I am afraid of reporting wrongly. It has been weighing on me all week. 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.