I would expect they took note of all that somehow when they took the items.
Do you take note of every time you take a pen, a pad of paper, or a screen cleaner from your employer's office supply cabinet? I don't. My employer only has a sheet where one is supposed to make a note if some type of supply is running low. (Some companies reportedly do require employees to record every pen taken, every pad of paper taken, every packet of screen cleaner taken. From what I've heard, it is a huge pain in the rear.) The office supply cabinet is there to easily supply supplies so as to makes the people who work their more efficient.
This was the first SpaceX flight with people aboard. I would expect that SpaceX provided an excess of consumables, partly because in case of a contingencies that would make the flight last longer, but also partly because this was their first time.
The crew spent 18 hours and 20 minutes in the capsule between undocking from the International Space Station and the start of the deorbit burn. Some of that time was spent watching over critical operations, some of it was spent sleeping and eating, and some spent for needed downtime. That still left a good amount of time. Allocating time for taking inventory so they didn't have to record each time they grabbed a bottle of water was a useful allocation of time.