I just finished the KDP publishing process using a Mobipocket Creator generated .prc e-book.
Everything went fine. Except KDP reprocessed my file, removing my perfectly calibrated cover and replacing it with an automatically generated cover image that has compression artifacts; this is a known issue. If anyone knows how to force a particular cover image file for Kindle, please share.
After KDP processing my e-book became 9 kilobytes larger.