Damage Mechanics

I'm a bit baffled by some of the mechanics. Maybe someone can clear it up for me.

My main skill (Blade Vortex) was at 2031 tooltip damage. I slotted a +15% Phys Damage jewel, and the damage went up to 2096. That's an increase of 65 damage, or 4.33 damage per percent on the jewel.

Then I took the jewel out and accepted 16% phys damage increase from Oak. My damage went up to 2096.5.

So...how does a 15% increase add 65 damage and a 16% increase adds 65.5 damage?
The math escapes me here...


Anyone?

The wiki has some in depth math if you want to learn it. But the simple answer is that anything that says "increased" or "reduced" gets added together to form a single multiplier. So if you already have 100% increased damage, 15% will give you 115% increased damage and 16% will give you 116% increased damage. You can see the difference is small.

I understand the concept, but whether i'm at 115% or 315%, the first 15% added 4.33 damage per percent. Why the NEXT 1% only added 0.5 damage makes zero sense.

You're going to have to give more information if you want somebody to show you the math. Post your skill tree and items (or unhide your characters) and I'm sure somebody can do the math for you.