Plugin for digital products that allow licence discounts based on quantity

Hi,

I am looking for an eCommerce plugin that would allow users to buy and download a digital product, but the cost would depend on the number of venues they would need to use it at.

For example:
1 -5 venues: cost £20 per licence
6 – 10 venues: cost £15 per licence

I would like it to be as seamless as possible, so the user would just enter a quantity, and it should do the calculation (price x quantity) for them and they would proceed to make the purchase.

there is only one digital product, that will be available once they have paid.

I’ve asked Easy Digital Downloads if they do something like this, and they say not at present.

Any assistance would be appreciated.

Thanks!