A divine ability equals 1 ECL.
4 Artifacts equal 1/3 of ECL
For each artifact you exchange you get divine abilities equal to 1/12 of ECL.
So for example a greater deity 80 level wizard will have 160 ECL,
if you exchange an artifact for divine abilities you will get 160/12 = 13 divine abilities rounded down.
That is very strange, at that exchange rate you would effectively double your divine abilities for one artifact
With the case of the wizard what reason would i want to keep an artifact that gives a q80 to int but rather gain an additional 13 divine abilities? And i can do that four times. 16 from template + (13×4)
16 to 68 seems like a massive jump
Well thats the math, but by the way I would never use an artifact that just gives a bonus to intelligence as you suggest, in fact most of the artifacts I use give divine abilities or their equilavant to their user.
What?