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. I would rather hear the honest version than the polite one. Pay posts on a different day from when I work. Do you report when you earned it or when you were paid?

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

Thanks for writing this out. I went through something close to it 6 months ago, and it got easier once I kept a simple log of every call and form.