Dave is a pain. Using old numbers is a band-aid, not a fix. But if you’re stuck, maybe the first step is admitting you’re stuck. Not to Dave, but to yourself. You’re not moving because you’re trying to be perfect.
Try this: Close the spreadsheet. Walk away for ten minutes. Get water. The brain works better when it’s not staring at the same six cells. If you come back and it’s still there, you’re not assessing, you’re stalling.
And if Dave pushes back, tell him the risk. "If we use old numbers, we’re hiding a $412 error. That’s a compliance issue." Make it about the risk, not your time. He can argue with time. He can’t argue with risk.