I was in the initial Beta test phase in 1988 for Callahan and Roach flat rate and I wrote the flat rate software as a Board member of Excellence Alliance. I have been on flat rate for over 30 years. This program is by far the best that I have seen. It utilizes multiple pictures so homeowners understand what is involved in the repair. I comes with a preloaded inventory which is fantastic since we only need to tweak some items. I am using it with Service Titan and it is seamless. If you want a flat rate system that’s easy to use but very detailed I recommend Profit Rhino.