I finally contacted contacted Micromat about TTP8 not working in El Cap and got what I consider a BS response:
Lou
The program must be tested with the final release of El Capitan before we can release a version that we can know to be fully compatible with it. The beta program is covered by a non-disclosure agreement, and is not discussed in the forums.
Apple not only reserves the right to make major changes in the final release that were not in any of the betas, they have already done that before, with serious consequences for disk repair utilities. When Tiger was released, Apple added a disk directory file, the Extended Attributes file, that was not in the Tiger betas. Any disk repair utility that did not take the Extended Attributes file into account caused damage to it. A volume with a damaged Extended Attributes file would not mount.
Lou