From what I understand, the current BaseCamp 4.4.2 is not usable for Zumo 66x users. MapSource (as a recommended workaround by your CSRs) started crashing with the 2014.10 maps. If there was a database structure change at that time, would a simple recompile of MapSource use the current structure definitions and stop crashing.
Test case for MS: use the Route Tool to make a route from Newport, TN to Johnson City, TN. It will crash with the 2014.10-2015.30 maps.