Are you saving the new rev template to the revision table template path specified in your System Options>File locations?
How are you creating the custom properties? Type the codes into the cells: $PRPSHEET:"Mass"
Is your typing correct for the property (property name and $PRP vs $PRPSHEET)?
Does the property exist? Does it have a value?
My attached works without any issues (SW 2015).
Change the mass units in the part and it's immediately reflected in the rev table.
I am checked per Mr. Holliday's post.