I'm not sure I'd trust Permawash's claimed numbers. They are so far off everyone else's results that I suspect they are unadulterated voodoo marketing hype.
OK ... Lets talk prints, since paper based prints are the real test of washing. The numbers might work if you have one single very low key very dark print with little silver to be removed, fixed in pristine absolutely fresh unused rapid fix just mixed in two baths used something like the Ilford method, absolutely fresh unused Permawash just mixed, all for only that first single print being treated, and a deluge of water blasting over the print in an utterly wasteful manner.
Maybe. Maybe for that first single print, if handled perfectly, just one print so all solutions are working at utmost performance. But I wouldn't trust the claims even for just one print. I can't see how any wash aid can so greatly outperform very similar competitors.
I am sure Permawash is a very good product. I have used it. I have some now and use it without worry. Just not for such short process times. I don't believe in magic or miracles.
Not that I am being a negative-nelly just to be mean but... how do you know it works? The best test for proper fixing is to look at a print in say... 5 years to see if it has suffered from insufficient wash after fix. Have you been using the product that long?