It might help your sale if you mention the 2nd user programme offered by Formula Dynamics. Whereby they reprogramme the module to the new owner's VIN. They also test the module and provide support. For a fee but its very reasonable. I think FD recommend the seller send the unit to them directly as part of the deal. There's more info. on their website.
Full throttle/high RPM gear shifts are no different with the module.
It simply makes the gearbox think you are changing gear at full throttle/high RPM but you are in fact not.