I lost count of the number of games in my backlog, so a while ago I tried a similar spreadsheet. Mainly to stop me from replaying game I already finished multiple times and focusing on others instead. However, that felt too close to work instead of fun, so I gave up and went back to my favourite classics.
yeah i really feel that. according to steam i have 220 hours in resident evil 4 just replaying it over again or playing mods for it etc. having done my spreadsheet i've really felt a sense of completion when i complete games. i felt it heavier on games i spent more time on as apposed to games with like 15 hours.
edit:
just checked my steam and my most played game is starbound at 264.8 hours and i've only completed it once and played modded the few times after.