So one is paying the $300 extra for this customer service and post sales support? Why is it needed? Are their computer so unreliable that you need to pay a premium in advance so that you get support? And, of course you would go this direction since you will be making much more profit in this deal.
FYI, I have been using Scubapro, among others, since circa 1995 and they have ALWAYS taken care of me, my customers and students in the rare occasions there was a need for the mfg's support. In fact, I have a case now where one of my former students had an issue with his old SP dive computer but SP decided to offer him their newest dive computer, with loads of new features, for a token price. The shipping charges were more than what he had to pay to upgrade. The issue with the old dive computer is attributed to him but SP still took good care of him.