. . .
I have samples of both in front of me and the braid is not the same. Power Pro has a thicker coating over the line compared to Tuff.
Ah, the infamous PowerPro "gunk." It was initially marketed as a "feature" which gave the line "extra body" (sort of hairspray for fishing line), presumably to reduce wind-knotting in sub-40# Spectra/Dyneema. In the over 50# sizes that has not been a problem in a long time if it ever was. The coating might also have made otherwise coarse line a little easier on the fingers, too.
As for TUF line and PPro coming from the same city, I understood that there are very few mills capable of spinning fishing line from the stuff--maybe only one in Grand Junction, CO-- and that they, like gasoline refiners, ran batches set up according their clients' specific directions and recipes (12-bundles, so many fibers to the bundle, 16 strand, so many fibers to the bundle, etc.) Brand X one day, Brand Y the next.