How do you report hours that vary week to week? - 13 weeks in

I picked up part-time shifts as a payroll clerk and I am confused about how to report them. There are 12 people counting on me, so I am trying to be careful. Sometimes my paycheck is late by a week. Did anyone get an overpayment notice from a mistake?

Thanks for writing this out. I went through something close to it 10 months ago, and it got easier once I kept a simple log of every call and form.

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