I haven’t dived into the code much and could be wrong about all this, but for your first question, we use the “done with” setting in the EOB Posting page combined with “Mark as Cleared” in the billing manager to reset to primary. I think the “Undo checkout and reopen” button relates to the encounter/fee sheet, not the claim. Not sure what effect if any it has on the billing status.
Regarding “Validate and Clear”, there is a thread on here where that is discussed, but not sure it has been fully explained. We don’t use it, but have interpreted it to mean that it replicates what would happen if you combined the steps of “Validate only” on the claims, then a “Mark as Cleared” on all of them. Perhaps the utility of that is when you want to check the batch file but know you won’t want to submit the actual X12 produced?