The "% of" box on the Calculations admin page gives you enormous power and flexibility in all of your formulas. This field allows you to add a flat fee to your cart, or to multiply a percentage in the "Tests,Values" field to any combination of subtotal, tax calc, shipping calc, and any custom calcs that you have set up in your cart.
Here's a brief explanation of their function:
- - Not A Percentage - adds a flat fee to the subtotal
- Order Subtotal - % * sum of all items in cart
- Taxable Subtotal - % * sum of taxable items only
- Pretax Total - % * (cart subtotal + any pre-tax calcs)
- Pretax Taxable Total - % * (sum of taxable items only + any pre-tax calcs)
- After Tax Total - % * (cart subtotal + any pretax calcs + any tax calcs)
- After Tax Taxable Total - % * (sum of taxable items only + any pretax calcs + any tax calcs)
You may need to experiment with these choices to get the results you're after, i.e. choosing "% of Taxable Subtotal" works best for Tax calcs when you have customers set up as tax exempt. "% of Order Subtotal" charges everyone tax, no matter if their exempt or not.
Once you get the hang of this function, you can make SurfShop do almost anything you want it to!