TL:dr -- Is there any reason to NOT use Gasflux Type-U paste with Fillet-Pro?

Long version -- First off, I love using Fillet-Pro. Silver with enough "body" to create a decent fillet without having to possess Fattic-like brazing skill using 56%. But Cycle Design fluxes give me worms. I bought a small tub of the Fillet-Pro-specific flux maybe three months ago, and much like the stuff I bought 2 years ago for 56% silver, it has become a slurry of large solid granules. Basically unusable. I'm done with the Cycle Design flux.

I did some work with the Fillet-Pro on Sunday and yesterday using Gasflux Type-U flux (from Henry James). All the Gasflux fluxes seem to be far more stable over time in my garage. Anyway, it seemed to flow and work just fine, but I'm no chemist and don't know if there is anything I can't see going on. Is there any reason to NOT use the Gasflux Type-U with Fillet-Pro?