I have PPro C5 5.0.3 full version (no trial) AVCHD footage taken by Panasonic TM-700 and I am not able to use level effect for two reasons:
histogram is not readable being compressed on the horizontal axis
separate setting of RGB is not possible
I have seen previous posts on this issue and I have understood that the second point is a bug that will be taken care soon ( I hope) by ADOBE.
What about the first one? I found a post (387574) months ago dealing with this problem but the recomendation was strange (to mask the letterbox image) I can not believe that is the right way to proceed ! Same level effect on DV footage is OK.