Hi Leah,
I do not level until I have my slides out if that is what you are asking. Here is my reasoning. First, that is what my directions say and, second, I was in a site that was very far from level, I put my slides out, opened a basement bay door then leveled...once leveled, I couldn't close my basement door because of the torqued frame (not close!!!). I sure wouldn't want to put slides in or out with a frame that severly torqued. I'm sure this response will draw additional comments. I hope this addresses your question.
Tim