Then when you return to level 1, that smaller size to the stored morph target and restore the original size. When you divide the mesh, the smoothing algorithm causes the mesh to contract. Could you show examples. So now your level 1 is with how I imported. Did you try exporting to.
Rotating also changes the effective axes for this object. ZBrush will polish the whole surface while maintaining PolyGroup borders or creased edges. You can the switch to the transpose line to do the posing. The Rotate slider rotates the object around the selected axis or axes. I have a pair of pants for a character.