Pricing depends on his overhead and what he is doing. When I price a
job, I bid what it will cost ME to do it plus reasonable profit. My
overhead is higher than some other contractors, lower than some other
contractors. I often do duct mods that others ignore.
I am certified air balance and certified residential energy auditor.
Simple replacements I am not competitive, but I can do air balance work
that others can not do at any price.
Not trying to be the cheapest or most expensive, just the best.
Not the answer you were looking for maybe, just rambling. The answer
for you is that he is more qualified than most contractors, that is
worth something. Whether to go for the high end system depends on your
utility rates and bills. Also high end systems often provide better
comfort and reliability, but it is hard to put $$$$ on that.