Heradot, I doubt that any of the 260 lb Vibraplanes are sliding away with the addition of a record on the platter. My point is that because the Vibraplanes (and other air suspension systems) need a compressor to remain inflated in the long term means that at some interval, the air bladders need to be filled up again slightly. My compressor goes on for about 5 seconds every day or two. I can't hear it so it does not matter. It is supplying three Vibraplanes with 270 on each unit so there is a lot of pressure and air does escape slightly.
Because the unit needs air occasionally, it is changing very slightly in height or level or both. That is why it has automatic self-leveling. It follows that any part of the turntable system (motor, flywheel etc) should not be located on a different surface if absolute control of the dimensions within the system are to be maintained.
Perhaps this is only theoretical because it may not be heard, but then we are also talking about the accuracy of the Timeline vs the KAB and other devices. To remain consistent, if one argues for the Timeline, he should also argue for a fixed/closed motor pulley to platter distance, spindle to pivot distance etc, etc. How can it be otherwise?
As far as the thread is concerned, all of the Brinkman and TW Acustic BD tables I have heard and seen maintain this fixed motor to platter distance because they are placed on a common platform.