Is $5,500 to install TPO on a 200 sqft flat roof a fair price?

I am building a detached garage with a 14x14ft (approximately 200 sqft) rooftop deck. I plan to use a TileTech pedestal system that will sit on a TPO subfloor and drain through a parapet wall into an exterior gutter. The roof is rectangular. I received my first estimate for TPO, and at approximately $27 per square foot for 60mil TPO, this price struck me as high, even though I am located in Northern California. I am seeking opinions on whether this seems reasonable.