The >6 is accounted for in the column:
Since DiscountMin is 6 it should only discount the 7th and above and you shouldn't have to account for that elsewhere. Maybe I am confused about how they are added to the cart.
Do you have a sample url. Do the clubs show as separate line items or is this through the quantity. I may have been answering the wrong question this whole time since I never really knew the context I had to make some assumptions in my advice that I now realize may have been wrong.
None of what I said may be valid. Do you have a sample URL so I can see it without discounts. That will give me better context from which to answer.