That seems crazy high too though, I just got a 5 ton for a 2300 sq ft house with 12kw heat strips including duct work for 10k. The duct work was $3800.
I agree that seems expensive, but I wouldn't be totally shocked if a high-SEER, "name brand" unit with a pricey contractor could get that high. I had >100% cost variation for similar equipment between HVAC contractor quotes the last time I replaced a unit.
Yep, the price delta is definitely because of the high seer rating. That being said, we were quoted about the same price for a 16 seer unit from another contractor (McCarthy). It's definitely worth shopping around.