Alright, I've been doing some tests to get the different co-efficients for Consecration and Exorcism for the spreadsheet (already PMed), when I stumbled on something very disturbing regarding JotC.
Consecration:
(To be read as follows: Rank x: Base damage per tick, Damage when using 222 spelldamage gear - co-efficient)
Rank 6: 64, 90 - 94%
Rank 5: 48, 74 - 94%
Rank 4: 35, 61 - 94%
Rank 3: 24, 45 - 76%
Rank 2: 15, 32 - 61%
Rank 1: 8, 21 - 47%
What was very intersting is that in contrast to normal spelldamage gained from gear, the spelldamage from JotC doesn't seem to be affected by the co-efficient decline when downranking.
Meaning that ALL ranks of Consecration gain 95% from the 219 spelldamage added by JotC.
After further testing, I also discovered that damage added from JotC is NOT affected by any multipliers like everything else (sanctity, imp sanctity, crusade, vengeance, avenging wrath).
This means that JotC will always add a static +26 DPS to consecration regardless of buffs or multipliers.
Consecration rank 6 on a humanoid (+3% from crusade), with 3 stacks of vengeance (+15%) and imp Sanctity aura (+12.2%) and 302 spelldamage (222 from gear + 80 from trinket stacks):
Test result 132 tick! Theorycraft: (64 + (302 * 0.95)/8) * 1.1 * 1.02 * 1.03 * 1.15 = 132.72 DPS
Add JotC ("26 DPS"):
Test result 159 tick! Theorycraft: 26 + (64 + (302 * 0.95)/8) * 1.1 * 1.02 * 1.03 * 1.15 = 158.72 DPS
Instead of 167.27 DPS if JotC spelldamage was affected by multipliers!
Add Avenging Wrath (+30%):
Test result 199 tick! Theorycraft: 26 + (64 + (302 * 0.95)/8) * 1.1 * 1.02 * 1.03 * 1.15 * 1.3 = 198.53 DPS
Instead of 217.45 DPS if JotC spelldamage was affected by multipliers!
As you can see, damage gained from JotC does not benefit from any multipliers
Summary:
-Spelldamage added by JotC does not receive a penalty coefficient when downranking
-Spelldamage added by JotC does not benefit from any multipliers
-JotC will always add "26" more per tick to any rank of consecration regardless of buffs or multipliers
Exorcism:
I did not have time to test this fully and somehow I think it's silly to downrank this spell, given that max rank (7) exorcism costs 340 mana every 15 seconds, which is very little.
I suggest you just model the max rank, which receives a 43% co-efficient.
Also regarding JotC the same behavoir can be experienced as with Consecration, it's rank independant and multiplier independant, meaning JotC always adds 94.17 to any rank of exorcism regardless of multipliers/buffs.
I'm afraid through this bit of testing I've discovered a glaring flaw in one of our core abilities (JotC), I wouldn't be surprised if it gives a static buff that doesn't benefit from any multipliers on all abilities (SoC, Holy Wrath, Crusader Strike atm).