How do you report hours that vary week to week? - first time posting

I picked up part-time shifts as a quality inspector and I am confused about how to report them. I worked as a quality inspector before this. Pay posts on a different day from when I work. Did anyone get an overpayment notice from a mistake?

Thanks for writing this out. I went through something close to it last year, and it settled down once I kept a simple log of every call and form.