If you are doing special orders in your shop, what I suggest you do is put the special order into the computer and bill from the computer. Here are some reasons why:
1) Your pricing is transparent and everyone can see how it is calculated,
2) You charge the right amount for it, one of our clients told us that since he put a computer in, they have picked up a lot as they were often not charging for some options.
3) It makes it easy for the person working the till to run through the current options to the customers.
4) The computer makes a professional worksheet for the person doing the job to follow.