So I have been doing some math recently on the damage output of spells for my sorc and it just occured to me that my secondary element only has a MCL of 18. (20 cl + 1 enhancement - 3 air savant capstone) Well so I went and did some testing and I am a little bit confused on the results of the damage output. i was testing two spells, Otilukes Freezing Sphere and Polar Ray. My Caster Level for cold spells is 25 (20 + 5 draconic + 3 enhancements - 3 air savant capstone) while my Max CL is sitting at 18. Since spell damage no longer increases when the MCL is reached, these spells should be doing the same damage, they are both capped at MCL 18 so they should both be doing 18d3 + 54. (instead of Otilukes being 20d3 + 60 and Polar Ray being 25d3 + 75). My testing though shows that polar ray is critting on average for about 200-600 more then Otilukes is. It is also apparent that the -3 MCl and -3 cl from air savant capstone is applying because when I take it off there is a clear difference in damage.

Am I missing something obvious here or is something not working properly.

So even though my MCL is 18 is it giving me the level 20 cl since that is when the spell actually has its normal MCL cap? And is polar ray giving me cl 25 even though the mcl after being modified is 18? I could probably figure this out with more testing but I would like to know if anyone knows.