Masterworks question?

Items and Crafting
1

I had an item that had 1 high stat roll on my 2-handed weapon. It had +2620 to life. I did Masterworks, which says add 5% to every stat. When I was done, it said +2707 to life. That means 87 life was added.

But 5% of +2620 would be 1/2 x 262 = 131. So I should have +2751 to life. All my other stats had 5% added correctly.

Tried looking through other topics, couldn’t find this issue anywhere else. Explanation please?

2

I didn’t notice this but my guess is 5% of the base value.
That 2620 is a greater affix, which means it gains a bonus of 50%, while the real value of a regular affix on 2H would be 1746.
So the 5% is of the base value of 1746 is additive with the bonus from greater affix, leading to a total of 55%, which doing math gives 2706.3