Enforcer my friend and Compadre.........
Material is more and the tools and experience to install is greater. I have NO idea concerning the Local Pricing. I have not touched a Roof since I was in Atlanta!
I have ALWAYS used Firestone Granulated. If not granulated you need to Aluminum Coat one-month later. Then sell them a Service/Repaint Contract.
http://www.contractortalk.com/f15/favorite-torch-down-material-53661/
http://www.contractortalk.com/f15/flat-roof-question-14556/
Protrusions are what make the Flat Install pricier. Stink Pipes, Vents, Skylites..........All of these things need be wrapped in a VERY particular and time consuming manner.