Can you give me a price based on a print-out from the internet of a house plan?

Internet house plans are extremely difficult to price accurately because they do not show the elevations, ceiling heights, special ceilings (treys, barrel, coffered, vaulted) and trim, window and door dimensions, and most importantly, they do not show any room dimensions.  Many times they do not show special features the architect has designed for the outside of the home such as stone, shutters, special shaped windows, arches, etc.    I can provide a potential customer with a ballpark figure for the home based on an internet drawing with the understanding the price will probably go up once the home plan is ordered and re-priced based on actual plans.