Is there a way to ensure that when a coupon code is used on an item in the cart that Custom Option Modifiers are not included in the price deduction if percentage discounting is used?
For instance, since we have certain requirements on the shipping and processing availability of each product we offer, we have to roll shipping into each item while still allowing them the option to choose what kind of shipping, so shipping becomes a custom option modifier on the product itself.
Let's say we have a Fancy Vase priced at $50. Shipping for the vase can either be free, expedited ($5), or next day ($10). If someone uses a 10% off coupon, we want to make sure that $5 is the only thing deducted from the price of the item, not $5.50 (for expedited) or $6.00 (for next day).