The trends in the CE/VE were different between the 1-10, 11-50, and 51-75.
Code:
Level CE Mod VE Mod CE Mod VE Mod
75 0.727 4.36 40 / 55 240 / 55
76 0.727 4.36 40 / 55 240 / 55
77 0.714 4.29 40 / 56 240 / 56
78 0.714 4.29 40 / 56 240 / 56
79 0.702 4.21 40 / 57 240 / 57
80 0.690 4.14 40 / 58 240 / 58
81 0.690 4.14 40 / 58 240 / 58
82 0.678 4.07 40 / 59 240 / 59
83 0.678 4.07 40 / 59 240 / 59
84 0.667 4.00 40 / 60 240 / 60
85 0.656 3.93 40 / 61 240 / 61
86 0.656 3.93 40 / 61 240 / 61
87 0.645 3.87 40 / 62 240 / 62
88 0.646 3.87 40 / 62 240 / 62
89 0.635 3.81 40 / 63 240 / 63
90 0.625 3.75 40 / 64 240 / 64
This is what the CE/VE modifiers would look like if the trend observed from level 51 onwards was continued. There's a fair chance that this might not be the case because trends in other parts of the game did not continue the trends they were exhibiting before. The alpha value used for WSC, for instance, decreased at periodic intervals from levels 1-75, although after that it increased ending up at 0.85 at level 90.
Either way, if you want to test what it is at 90, it shouldn't be too hard if you can get some people to help you. 40/64 is a good starting point value for going about these tests. I would recommend doing this.
You'll need three people with +/- 0 enmity. If you have merits find some gear to zero it out. Any job that can get Stoneskin works, one of you will need Cure III. I recommend BRD, the CE gained by some of its spells are convenient.
Player 1/2/3: Puts up Stoneskin, should all have full HP.
Player 1: Pulls a mob and pulls it near a zoneline where the other two people wait. Then, changes gear to reduce their HP total by 100, then change back (thus reducing their current HP to exactly 100 under its total.)
Player 2: Casts Cure III on player 1 to cure 100 HP. Then casts a Cure I on player 1 for 0 HP.
Player 3: Casts a Cure 1 on player 1 for 0 HP.
Player 1: Zones
At this point, player 3 needs to do actions to generate more CE. VE will probably be generated too, so be aware that you may need to allow it to decay before doing another action. I recommend BRD for player 3, after doing the 0 HP cure to get on the hate list, they can then move back (so their songs only hit themselves) and cast two of the buff songs that generate 20 CE each. This would put them at 41 CE. After the mob turns back to player 2 (from player 3's VE decaying, player 2 should almost certainly have more than 41 CE), have player 3 cast Cure I for 0 HP over and over until it turns. It will turn when their CE is equal to player 3's, which will be going up by 1 at a time.
Code:
Modifer CE Cures
40 / 57 71 30
40 / 58 69 28
40 / 59 68 27
40 / 60 67 26
40 / 61 66 25
40 / 62 65 24
40 / 63 64 23
40 / 64 63 22
40 / 65 62 21
40 / 66 61 20
40 / 67 60 19
40 / 68 59 18
This is a table for various CE modifiers and how many cures it will take player 3 to finally pull hate. It's highly likely that the modifier is in this table and it covers all of the distinct modifiers without any overlap. Since the numerator for the VE modifier is always 240 and the denominator always matches the CE denominator, this test will find that as well.