Durkon's Caster Level

[Thanatosia]

So, long waits between comics means a lot of browsing of back issues, and while rereading the Siege of Sapphire City, I think I found something I never realy thought of before: Durkon can dispell Xykon's Spells (http://www.giantitp.com/comics/oots0429.html) but Redcloak can't dispell V's (http://www.giantitp.com/comics/oots0653.html)

The standards i've been going off of had Durkon around lv12-14 by the time of the Battle of Sapphire City, Redcloak around 16-17ish, and Xykon is lv26-27ish. Does this mean Durkon's caster level is significantly higher then that, or that Xykons is somewhat lower?

[spargel]

Maybe someone else casted Greater Invisibility.

[Felyndiira]

Durkon's caster level is not significant, since greater dispel caps as CL +20 anyway. Thus, he likely just rolled high enough on the d20 to dispel Xykon's invisibility.

Redcloak's inability to dispel V is the result of V's effective caster level being the sum of his two soul splices, putting him somewhere way above level 19 (the highest CL that dispel magic can remove).

[Liwen]

Azure City!

[King of Nowhere]

Durkon was 13th during the battle. If we assume Xykon is 22-23 (and cast maximized energy drain thanks to some item, otherwise he would be at least 26) Durkon could dispel the invisibility with a lucky roll.
If we assume Redcloak to be 15th (evidence of it, no evidence of higher level) and the spliced souls to be around 25 (Haerta higher), Redcloak either can't dispel their spells or could only with a 20 or 19. So the best explanations are either that Durkon just rolled high in that circumstance, or that someone cast greater invisibility.
To be noted that When soul spliced, V did cast fly with his own power (already had it when attacked by the dragon). Since Redcloak didn't dispel it, he probably rolled low.

[the_tick_rules]

Are we talking about V when she was boosted by soul splice? Or how about favorable or unfavorabe dice rolls?