I am not sure where (mou, contract, hr doc) but I believe there is a pretty strict timeline that needs to be followed. My coworker that got approved for hardship and left breifly talked about it. Said something along the lines of local has like 7 business days to make sure it is valid, then the natca region hardship person looks at it, followed by the hardship people for the FAA who make the final call. Then if it is approved they look at gaining facility, staffing, etc... I believe if it is a valid reason but it can not be granted due to outside factors such as staffing then it must be looked at every 6 months until it reaches final approval. These are just estimates of numbers but that was the gist of what he went through. It should be pretty straightforward on the moving up the channel part as everyone in the process has a certain amount of business days to make a determination. That was about 3 months ago so maybe things have changed since then