What makes a time-sheet valid and invalid in the state of Montana?

I am a California attorney and cannot give legal advice in your state. My comments are information only, based on federal law and general legal principles. YOUR STATE MAY HAVE ITS OWN LAWS THAT OFFER SIMILAR OR GREATER PROTECTION. If I mention your state’s laws, it only means I did a quick Internet search and found something that looked relevant. You MUST check with an attorney licensed in your state to learn your rights. This is a really open-ended question. I could probably write ten pages or more in response to your question. It would be helpful if you would ask a specific question. Tell us what prompted your question.