Meda Rodate, manager of the Turquoise Oasis Spa, wants to improve the layout of the existing spa invoice and automate the invoice process as much as possible to ensure data accuracy and consistency. The invoice currently has formulas in the Charge$/$Hour and Amount columns, but they often get deleted by mistake. The Therapist name is often misspelled, the room number is often wrong, and Meda thinks the subtotal amount may not be calculating correctly. Another problem arises when the description of the service is not entered correctly, and then the charge$/$hour cannot be found in the lookup table.