How do you report hours that vary week to week?

I work some days through a staffing agency while still certifying. There are 6 people counting on me, so I am trying to be careful. Pay posts on a different day from when I work.

I estimated and then checked my pay stub. When there was a small difference I wrote to the agency to correct it.

Report honestly and keep your stubs. An honest small error is much easier to fix than a missing report.