I recieved the files this morning and the first steps - importing, formulas for totals, profits, etc, seem fine. But, after that, what is the logic, bar trial and error, for the units to be built, save there can be no more than 200 of any type. How will the margin be set? How will we work out what features to add? Is it simply the painstaking task of trying each figure, for each feature, from the dropdown lists?