What determine's a Combo Skill's level?

[ziv]

When a combination skill goes off (such as Mind Breaker or Hell Fire), what determines its level? Is it the average of each of the two spells that set it off, or is it just based on one of them?

[Balathorn]

The effectiveness it determined by the lowest skill level at the lowest upgrade among the two (or three in the case of bursting beam)

[LostCause]

Depending on what combo you are pulling off but the lowest lv of the 2 or 3 skill that is used will determine the dmg lv. so if someone have a lv 1, your combo will be lv 1 regardless if the other is lv 60.

[nem4z17esis]

Damn, I thought it would be the average of all the characters skill..