I made my own flat rate sheet on excel and to be honest, it came out way too complicated to be practical (in the field anyway). Did you make this yourself or do you have rhino or something similar?
I also made a sort of flat rate sheet but only for materials. I got tired of writing up materials lists for each job, many the same over and over. Each column on the spreadsheet is a device or outlet, such as, box, duplex TR receptacle, GFI receptacle, S1, S3, ceiling light, wall light, etc. In the far-left column, I list all the items that are needed, such as the device, cable / wire, cover plate, staples, connectors, wire nuts, etc. So there is one lump price under each device, or item, including tax and my markup. I separate things like old work, new work, exterior, recessed lighting, and others on different pages of the spreadsheet. I do this in Google sheets, so when I'm giving a price in person or in the office, I can refer to my material prices and items using my phone or computer. Then I add labor for the whole job based on hours its going to take. I still need to price certain things and have to keep on top of wire prices. These days you blink and prices are 20% higher.