Pack and go - read only dimensions

I'm building sub-assemblies with parts saved externally.  Each part size is referenced back to the properties w/in the sub-assembly.  To save time I use PackNGo through explorer to create new parts, I insert them into the sub-assembly and need to make changes to sizes. When I try to do that, all the dims are now read-only, and I have to uncheck the box for each one, at which point it lets me modify/reference the dims.  Is there a way to have that by default not be "read-only"? I've got so many parts that it adds up taking the time to uncheck all the boxes.

Thank you

Dan

SolidworksParts And Features