It means you should be able to play the game at max settings at 720.
And you should be able to play the game at default settings at 1080.

Benchmarks are to determine at which specification you should set the game for best overall gameplay.

For example you got over 10k on medium on 720 that is way to high of a score which means you can play it at a higher setting, than you tried with everything on maximum and got around 3.2k which is alot lower. Which means you dont want to play the game on medium settings cause your computer would kill the game, but you also don't want to play the game at maximum settings cause the game would kill your computer. So you would want to play around with the settings a little bit and find a place that is inbetween medium and maximum. Judging by what you say I would start with 1080, and maybe do medium settings at that resolution.