I, too, have noticed the new labels for Testor's glosscote, and they have a new model number, two. The new labels call it "General Purpose Clear Laquer" and I have avoided it and kept using the old black label model master can, its model number is 1961. From the above reports, it sounds like the stuff with the new white labels is indeed a different formulation.
I am going to hit the local Hobby Town today and stock up with the old 1961 model, hopefully they still have some- as it works well as Don said. I don't known if Testor's plans to continue manufacturing both kinds or not.