I have just created a new line item and found that updating prices by the gp, to be very easy, and quick. It is not necessary to workout all your prices. Just make sure that you are consitent in the price that you are going to use as your base. Go to menu, then to invoice/ part utility/ price%. The screen will come up , you choose whether you want to adjust by % or GP. Choose the price levels you wish to adjust, next column put in the price field you wish to create you prices from ( ie: field 6), next column choose your gp % that you want. Check the preview button to see what it looks like. If everything looks ok, check the write to database box, update and your prices are set. You can check preview to make sure you like it. If not, do the process again