I have no clue what dyno time costs, but I'm willing to bet it is all of 750 a day ($75 hr seems reasonable for piece of equipment like that)
Assuming your initial numbers are correct 670+250 for dyno = one expensive stage two tune. That almost seems out of the question for those guys.
900+ for a tune that I will be getting is almost unreasonable ... Manitou and I talked about our concerns for this today.
I can't drop 900 on the flip of switch and I doubt most people will drop it period