Synchronization failures with large number of ship-to records - Sage300 v2012 and CRM 7.2

We have a customer with more than 30,000 ship to addresses for a bill-to record.  When they add a new ship-to record, they get a message that the ship-to synchronization failed.

We've been told that there is a limit somewhere around 1,000 ship-to records for a single bill-to record, and we've been told that isn't so.  

We really need to find a way to accommodate this requirement - has anyone had success synchronizing a large data set like this?  

We're on Sage300 2012 with SQL 2012, CRM7.2.  

Thanks.