Oh, I wasn't casting any dispersions on Polyphony. It seems like a really fine and necessary product in my opinion and I am glad to be able to use it.
I was more thinking of "garbage-in, garbage-out". In other words, I was worried that if I had an sf2 on unknown origin that had some things wrong with it, I might still be able to edit it with Polyphony, but some flaw in the original might still exist in the Polyphone output. For instance, if I were trying to make an sf2 with just one preset, as I often do these days, if there was a structural flaw in the original, it might just be passed on into the output.
But. at this point, it's more likely my program in development, which I'm working on right now. In iOS, the firmware and classes for sf2 seem to date wayback, including Apple DLS things. I'm glad to have it, hope to find the same on Android some day, but it is difficult to find much in the way of examples or documentation, aside from some excellent stuff from Gene De Lisa and Eric Ford. If you know of others about iOS sf2 coding, do tell.