Let me put it to you this way. If you had to detail the engine on a Hauyra, 250 GTO, Shelby Daytona, or anything that is really timeless and exotic, is a hose and some APC really the best choice?
I have washed both a 430 and 458 engine, and even after they were dried, the engine threw codes because the sensors were wet (threw a knock sensor and left bank cam on the 458 and 02 sensor on the 430). This is not a big deal for me, I allowed them to dry 100%, then cleared the codes, rescanned, no issues.
My point is this may seem like a stupid outrageous way to do something that only an idiot would pay for, but when you deal with really exotic cars, you don't want to be the guy that wrecks it!
I would also be very careful about knocking PD's work. Saying his $8K detail is no better than someone else's $800 (I don't know how you came up with this number) detail is really opening a can of worms. Its like saying you know as much as Mike Philips or Larry Kosilla. Daltons sheer experience and knowledge base, let alone his patience and ability to product flawless work is not something you trash on. Even on the big detailing forums, Facebook pages, etc he is very well respected by some of the best in this business. Not to mention PD is a very kind, lovely person to speak with and he is very humble and honest about what he does, same goes for Larry and Mike. I would have a little more respect for Dalton if I were you.