I took a look at your file and brainstormed the possibilities already. The exact format you described to add fixed cost by feature is not possible without changing some prices a little. If you are OK changing prices a little, I can do this quickly for you. If you want prices to stay closer to the same, we can discuss different formulas that keep prices closer to what you have in the file.
Let's discuss these options when you get a chance, I would enjoy helping you with this project!
~Mark, (MasterOfNumbers)
[100% completion, 100% on-time, 100% satisfaction, 100% guarantee]