Weird Mastery Count [CLIENT]

Honestly this isn't really a bug but I feel like this is confusing (and if I knew how to put pictures directly in a post, I would have done that but we'll have to settle for an imgur link for now)

Yes it says "Increases by 1 every time you unlock a Mastery level 6 or 7 on a champ" but I didn't think it meant literally. I really only have two 6+ Mastery champs but it's saying I have 3 because the Mastery 7 Leona counts as two. I just think that's a weird thing to have because it's not really accurate. I'm not entirely sure why the Mastery 7 counts as two points in that if it was intended, but it just seems a bit odd that it works like that.