Maybe this indicates that zero tracking angle error is not the Holy Grail some claim it to be.
That's the designer's whole point, right?
I suspect there are a few other things at play here beyond the TAE vs. skating force. From personal experience I can say that 3° TAE error on a conventional overhung setup is vastly different in sonic character than the same error on the 9" Schröder reference I set up as a 0 offset underhung arm. I purposely chose 3° TAE since it is beyond properly setup traditional tonearm error but guaranteed to occur on any underhung design.
dave