.PLN attributes are stored in the file and act independently. You would have to update each .PLN file.
.MOD files do not store attributes and act "transparently" with the file that they are inserted/Hotlinked into. You would only have to maintain the "master" file that you are working in.
Hope this helps explain.
David Larrew, AIA, GDLA, GSRC
Architectural Technology Specialist
a r c h i S O L U T I O N S
WIN7-10/ OSX 10.15.7
AC 5.1-25 USA