Jason and I pulled the chain on two monuments in the Y-END station and read it at 8536.5 mm.
We then setup the total station over one monument and the corner cube over the other.
We looked at four different corner cubes with and without the cross hairs and they all read consistently at 8536.0 mm (0.5 mm difference as measured by the chain)
We will next compare the other SET 1X total station using the same setup, but I don't expect to see much of a difference.

The distance from the TM HR face to the corner cube reference plate for the ITMy is 44.6 mm; and 43.9 mm for the ETMy so that shows consistency as well. The corner cube reference plate is 17.74 mm to the mounting surface that registers against the Quad face frame.

So far nothing glaring.