OK, I admit I dug up this thread again, but I have some relevant information for all to hear, as this may be useful in PvP.

I experimented with 2 Voulges. I placed a +9 max damage jewel in one, nothing in other. I then proceeded to place both voulges in my weapon slots 1 & 2.

The one with the +Max jewel's damage in character screen was: 11-60
The plain one's damage was: 11-42

It would appear that any +max jewels placed into a weapon affects the weapon's max damage, like it did back in 1.09.

So, to get the most out of your gear, it appears you want to get you desired ias out of your other gear with 40/15 ias and have 40'15 max's in your weapon, if possible.

Hope this helps everyone.