The numbers represent how difficult the hole is for the week. #12 being the most difficult hole, with #13 being the 4th hardest, in relation to par. So if the average for the hole is 4.56 on a par 5, it means that most players are making 5-6 strokes for the hole and very few shooting 4 shots from tee to green.
If your numbers mean that the 12th hole is the hardest (for the week and that is represented by a 4), then is 15th hole 3.25 times as hard as the 12th (represented by a 13)???
I don’t get how your numbers and your explanation match each other.
Your numbers seem all Greek to me.