A better and more accurate sorting "algorithm"

So I think the currently most accurate sorting by time played option is still too inaccurate, because as a metal fan, you often listen to longer songs, which means that songs will be higher.

So here is my really simple idea that would solve this problem:

Take the full length of the song, and that's 100%. Then it calculates the minutes you listened into percentage. And like idk convert the percentage to a simple number (63% -> 63 points), and always add that to the points of the song...

And if someone starts over, add the value and start calculating again.

If someone is jumping in the track back and forward then just act as if he always started from the begging.

For example: There is a 10 minutes long song. I listened to 3 minutes and 30 seconds, so I listened to 35% of the song. I skip, and I get 35 points in the statistics to that song

I know it's probably not that simple, I never worked with databases, but I believe it shouldn't be that hard either...