Can't you do something about the Ricoh Controller
Sorry Yannis, we don't have much influence with Ricoh …
I have also noticed that the clock (the internal clock that is) won't stay at 96000
Not sure that this means anything – any measurement may always have an uncertainty in the least significant digit. If you are hearing any "pitchy" effects when this happens, that would be another matter.
Using an external source will probably make this reading worse, since the clock will be unrelated. But, again, probably not meaningful.