Hi,
All those branches are connected via WAN links? Bandwidth size between main site and branches?
What's the source for those branches to receive definitions updates?
Could you please update total how many content revisions are saved by SEPM.
Best Practices for configuring the number of content revisions to keep in Symantec Endpoint Protection Manager:
http://www.symantec.com/business/support/index?page=content&id=TECH92225
If clients are reuesting full.zip instead of delta updates then bandwidht utilization can increaese.