There is a very important difference between a Discount and Store Credit. A Discount decreases the taxable amount of a transaction while a Store Credit does not. Consider the following:
Service = $75
Discount = $10
Final Total = $65
Taxable Amount = $65
In this scenario, the sales tax will be calculated on the $65 final total. The same situation, using Store Credit instead of a Discount, results in the following:
Service = $75
Store Credit = $10
Final Total = $65
Taxable Amount = $75
With this in mind, if you want to decrease the amount your client pays please use the Discount field in the Cash Register. You can find more about providing a Discount in the Cash Register by checking out our tutorial for Checking Out an Appointment.