How do you report hours that vary week to week? (update)

I work some days through a staffing agency while still certifying. There are 9 people counting on me, so I am trying to be careful. The form asks for gross earnings, which I do not see until later. Do you report when you earned it or when you were paid?

In my state the question was about the week I worked, not the week I was paid. Read the wording on your form carefully, or ask the claims line.