EDIT: And the mystery is solved! Huge thanks to Suicidal Zebra for pointing out where I went wrong and how to fix it. I’m going to leave this post here though, as it’s a good lesson for other number newbies like me who’re trying to figure how this mathematical magic happens.
You number people will love this one.
I promised I’d do some research to find the new spell coefficients for holy paladins. Since the tooltips weren’t updated with the paladin hotfix, I was left with the immense pleasure of doing it all by hand. So that’s what I did. I stood in Darnassus, hit a dummy to stay in combat and recorded my overheal as I showered myself with heals.
I tested all of our spells, approximately 50 hits per spell and was feeling rather smug about myself. Then I got the idea to retest the spells with a different spell power.
Surprise, surprise, they didn’t match up.
The equation: Heal output = Base heal + SP*Coefficient
I used the base values from Wowhead, which, for Holy Light are 2871 to 3197, averaging at 3034.
I made a special blank talent tree to avoid the annoying Conviction talent. I left my retribution glyphs in, but I checked several times to make sure none of them affected healing. Finally, I removed my Ashen Band of Endless Wisdom to avoid the spell power proc. None of the rest of my gear had any procs that affected spell power or healing.
My results with 3427 spell power were the following:
I used the crits as a second sample to compare values. Dividing the crit values by 1.5 produces 6014-6343-6742.
Both samples produced the same coefficients: 0.92 for the minimum value, 0.97 for the average value and 1.0 for the maximum value. While the coefficients don’t exactly line up, I took into consideration that the max and min values are extremes and concluded that 0.97 was my Holy Light coefficient.
Just to be safe, though, I retested it a few days later after removing some clothes. At 1968 spell power, I received the following values:
Dividing the crit by 1.5 produced 5533-5797-6040.
I plugged in my coefficient equation and obtained: 1.35 as minimum, 1.4 as the average and 1.44 as the maximum.
Again the crits and hits produced identical coefficients.
Which leaves me with the following theories:
1) I screwed up somewhere (that’s where you guys come in handy!)
2) There’s diminishing returns to our spell power, at least for Holy Light.
3) The spell power coefficient is now exponential.
4) We received a hotfix between my high spell power and low spell power testing.
I checked #4 by testing Holy Light at full spell power again, this time on the same day as my low spell power test. At 3622 spell power, I received the following:
The crit values, divided by 1.5 are 6111-6358-6579.
The coefficients for this sample are: 0.89 minimum, 0.91 average and 0.93 maximum.
Again, the coefficients for the crits and the hits are almost identical.
These results seem to suggest diminishing returns with spell power, at least for Holy Light: the more spell power we stack, the lower the coefficient.