Michael, that should read "Haist describes the effect of pH on washing". His publications were heavily redacted by EK. This was a case of my knowing what he wrote and what he published. Sorry, but you still have things backwards.
As for FB papers, the paper fibers have an affinity for hypo and other salts, and therefore washing is less efficient. The exposed Baryta also has some effect. There are articles out there on this.
The point is, that an alkaline pH speeds up fixing and washing and this is regardless of where it is applied after the stop or rinse step.
Kodak has sold an alkaline hardening fixer BTW, which was described elsewhere on APUG. the washing information in Mason has been reported at least 2x by myself here. We keep going over and over this same thing. It is really being worried to exhaustion IMHO.