Solidworks assigned mass is getting overwritten on rebuild

I have a column \$SW-MASS in an excel design table that assigns the mass for each configuration.

When I leave the design table, the mass looks correct in the mass properties window for each configuration.

However, as soon as I hit ctrl-Q or the rebuild button for a rebuild of a configuration, the calculated mass shows up again in the mass properties window for that configuration.

I also noticed that the checkbox for "Override mass:" is not checked, even though I am assigning \$SW-Mass in the design table.

Test part attached.

I would appreciate input, thanks.

Solidworks 2013 SP3

SolidworksParts And Features