New to Warcraft Logs, looking for some help with scores

Hey everyone. I just started using Warcraft Logs, and I was wondering why some of my scores seem to be different on the same log/kill. Maybe i’m just not understanding what the different values mean?

Here’s an example:

I only have 1 kill on heroic Imonar, and on this page I have it sorted by item level, which gives me a score of 51

But when I click down below to look at the log for the fight, It’s showing a 70% when compared by item level

Am I missing something here? any help/input would be really appreciated, thanks.