QUOTE(mouisaac)

Is there a way to see the invisible decimals?
At first, I try to make them equal but they always differ by a very small amount
As far as I know there is no way, you can only determine it experimentally by casting both types simultaneously and checking to see if they always stay the same, or occasionally become different.
To make your proficiencies change by a smaller amount, you must lower difficulty back to Normal. Everything will be invisible, so you'll have to check experimentally which proficiency is invisibly lower, then perform that skill alone against a single enemy, then check experimentally again.
I know it's possible because when the latest patch hit, my 1H and Heavy Armor proficiencies were not equal, however I was able to make them exactly equal again after hundreds of tries. At least, I have never seen the proficiencies become different after over a year...
As another test, before the patch hit I had exactly 0 Forbidden, 0 Divine, 20 Staff, and 22 Elemental proficiency. Now they are all at 338.565 however I did see the staff/elemental proficiency drift by 0.001 after very rare Dawns. I'm guessing when I hit level 390 they might be "exactly" the same.