Coupon Based on Sort Order (15x/2x)

What does it do:
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This allows you to set the coupon discount to be applied on the current sort order position instead of always applying to the product subtotal.
This is useful when you want to limit the overall discount when more than one discount is active, or apply the discount to other fees ahead of the total line.

For example, using the normal flow:
Subtotal: 100.00
Wholesale Disc (10%): -10.00
Coupon (10%): -10.00 <-- since this applies to the subtotal 10% of 100.00, not the current discounted subtotal
Shipping: 5.00
Total: 85.00

With this mod, you can use the current total based on the sort order:
Subtotal: 100.00
Wholesale Disc (10%): -10.00
Coupon (10%): -9.00 <-- This now applies to the current based on sort order after the other discount 10% of 90.00
Shipping: 5.00
Total: 86.00

Or if you move it below shipping:
Subtotal: 100.00
Wholesale Disc (10%): -10.00
Shipping: 5.00
Coupon (10%): -9.50 <-- This now applies to the current based on sort order 10% of 95.00 shipping
Total: 85.50


Requirements:
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* You will need to have the latest vQmod engine installed (http://vQmod.com)


Main features:
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* Simple vQmod script plug and play. No files to edit or overwrite.
* Coupon discount can be set to apply to any previous total value
* Coupons based on specific products are prorated for those products based on the discount difference.
So if it was 10% of 100, and there was a previous discount that brought it to 90.00 then it will take a 9% discount on the product.
* Existing coupon functionality doesn't change. Free shipping will still apply.