If I take a aircraft remove the cube and PDB and replace the plates its sitting on in the same position on new plates do I need to reperform the compass &or accel calibrations?
In the same vain if I pack a machine and ship it some where should I redo the compass calibration due to the machine getting jarred in shipping.
The calibration is hardware dependent, so if Cube changes, you need to redo the calibration.
It also depends on the location, so yes you need to redo.
No need to redo the compass cal because of location change. By default the declination table is used and people have successfully moved hundreds or thousands of kilometres without recalibrating - that is the desired action!
But I would recal if doing any changes to layout or wiring. Get a good 3D GPS fix before doing the compass cal.
How many people have tested this, at which distances? Can we have a show of hands?
At any distance. Compass calibration is to account for local, on vehicle, interference. This is often conflated with declination which is a global correction handled by the look-up table from GPS position.