When the shaman reaches the next stage, is the energy supposed to fill up?

It looks like I have reached the maximum % on sustained attack, where can I find out what the basic number of attacks is?

The shaman I am currently using is showing no sustained attack capability, which in some respects makes sense,as the current level is presently insufficient to open up sustained attack in the shaman's skill tree, however I have opened up the shaman sustained attack in the shaman knowledge section in the oracle.

Is this just display  or a technical issue?

Additional question.

Should you open up a higher stage if you have the charms, or wait till you have finished all the levels of that stage first?