Well, in theory, it shouldn't be an issue.
Each carrier is designed to handle a total of 96 Unit Loads.
Your 008-OPT Mods are rated at 13.5 UL Each.
Thus, 6 (The ammount you can put in an expanion carrier) would only total 81 unit loads.
That being said, the Pocket reference states that if the UL exceeds 96 per carrier, reconfigure the system to "spread out the load".
Therefore, we must come to the conclusion that 81 is too much for this puppy.
So, what is your config?
Can you re-arrange these bad boys to spread them out to provide a "SLIMMER" unit load on each power supply?
That's my story & I'm stickin' to it!