Was wondering if anyone has played around with the e-commerce discount module or created a custom discount type that applied the discount at the end of the order instead of after sales tax?

I know its weird but have someone asking as they want the discount to apply as the last entry item because some items may cost less than the discount but wouldn't if the discount also applied towards the shipping.

Hope that makes sense. Anyones input or advice on this would be greatly appreciated. I am sure its simple but while I am familiar with C5 I am not familiar at all with the e-commerce package.