Hi Capn Bloggs,
Have a look at Page 9
http://www.simdesign.nl/pubs/integra...ing_system.pdf.
"For example, a pitch up attitude of 20 degrees (common for the simulation of a take off) will reduce the available motions in all other directions and rotations to nearly zero,"
During a RTO, the pitch down of the box to simulate the retardation can be about 20 degs. That reduces the available rotations, causing the loss of vestibular feed back.