ok. I just achieved cl 6, which also coincided with OL 10, so I don't know which milestone triggered it.
I talked to brook and he gave me the recharge shield skill, and also the last stage of the missing transport mission, despite the fact that i gained 2 cl killing the cl6 and cl8 rd at the meeting point. Apparently, this must be completed before I can do the HU for lvl 10.
If there is a requirement to be a certain cl, why the heck does the skill not say so ffs. This needs to be fixed so that the requirements are clear as in every other skill.