7D 580ex trigger

I suspect that you are using a "mixed" mode of triggering and this is confusing the situation (and Scratchedisk and PJC Imagery). The flashes should be in non-wireless, standalone mode, and settings should not be made on the flashes, at least in Remote Control mode.

The 550EX (and the 580EX I) cannot be controlled by the 7D's flash control menus, and is therefore limited to those functions which can be controlled by the camera buttons. The camera + YN622 can control the YN622 + 550EX in ETTL with FEC; they cannot set Manual levels.

There can be a significant propagation delay when the flashes are used in this mixed Master/Manual wireless mode, and cause syncing issues.

The on-camera YN622 is the sole Master for the camera.

You may find by "The Other YN-622C User Guide" helpful:

https://docs.google.com/open?id=0B77OmmGIg0gMVFpqNkpBYXBHajA

--
Clive