The report length depends on how large the electronics department is at the store your auditing. I did one for a big box office supply store and they had only a handful a working demo units that would even power on and none of the things they were looking for. I still have not received any scoring on the report and it is in the "completed" status.
Doing the test took longer than the time spent in the store doing the audit and counting the items and then taking the photos they wanted. The manager was giving me the stink eye and started walking fast toward me right as I snapped the last shot I needed, so I just made a quick exit instead of having a confrontation and showing him a letter that was not a true LOA from that business HQ. The letter is more of a permission request and would likely be denied anyhow.
I'd do another one if it was close enough or I could find another job in that direction.
If you do take one for a store closed and send them an article from the local paper as proof of store closed, they will not pay anything.
It says to call the store first to verify they are open in the shop directions. They have nothing in writing about what happens if the store is closed as far as reduced or no payment. I would not drive out of my way to a store that may be closed as they may not pay you anything.