IGI at 4.5%, included or added
Type 4.5 as your tax rate once, for the whole business, and say whether your prices already include it. Most beauty shops do: the price on the shelf is what the customer pays, and the IGI sits inside it. If you price before tax, the till adds it instead. Discounts come off before the tax is worked out, and the till and the receipt show the tax with its rate above the total. Type IGI as the tax name in Company info, and the till, receipts, invoices and reports call it IGI.
How prices and tax work: VAT or sales tax