I know Richard won't mind if I have the last word on this since he is correct. I showed it to Dingle about 20 years ago, while we were in the middle of a drinking contest which I lost. It is not surprising that Dingle got it wrong when he showed it to Richard.
There does need to be a reason to turn the deck around. For example in a published ambitious card routine I make it the magic moment, “when I turn the deck around the card comes to the top again”. Since the publication of this move, others have come out with passes that use a revolving deck action as cover for a pass. Larry Jennings and Bruce Cervon come to mind.
An important feature of the Midnight Shift is that done correctly, it should appear to the viewer that the top of the deck never went out of sight. That is why it makes such a good color change. To illustrate, here is an idea by Bill Klaush. Have a six of spades on the bottom of the deck and hold a break over a nine of spades in the center. Say “if I turn a six upside down what do I get?” When the spectator says “a nine “do the move, “you are absolutely, correct a nine”.