How do you report hours that vary week to week? - 6 months and counting

I picked up part-time shifts as a procurement assistant and I am confused about how to report them. I have read a lot of threads here and could not find my exact situation. Sometimes my paycheck is late by a week. 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.