That's it, it was the rounddown!
Without it it adds up perfectly...I think I must have been thinking that you don't get an HP until you actually go up in health, probably I made the first version a loooong time ago
My actual health is 128.3 and so is my calc result now...on the other had it's too bad that the Melee skills don't help (directly) to your HP, since I'm much more Melee oriented then Ranged...then again, it's all in the game