Without a copy of the industry test procedure, it's easy to not have the same conditions, and the test results differ. In the tests done, it appears that the membrane tore at the top, which then peeled the rest off. Not being there, it's hard to say. I guess, though, that the bottom line is that properly installed, you should not worry about the tile coming loose on its own! If the industry test called for the tile to be grouted, this would also tie multiple tile together, increasing the overall effort required to pull any one tile out. Also, at least with the Ditra, the thinset doesn't really stick to the top side...it is locked into the wedge shaped pockets. So, the effort to pull it up is more of a function of distorting those pockets to get that wider base popped out of them, than the membrane breaking loose from the subflooring.