How to add a maximum fee

-- HikaShop version -- : 2.6.4
-- HikaMarket version -- : 1.7.2
-- Joomla version -- : 3.6.5
-- PHP version -- : 5.6

Hi there,

I hope you can help me clarify how to achieve the following.

On the Vendor fees I can add a flat fee that will be added per product bought and a percentage fee that will be on the total amount.

But can I cap the total fee to maximum value?

For example the flat fee per product is 1 euro and the percentage fee is 10%, but I would like to cap the vendor fee to a maximum of 10 euros.

That means if a customer buys 3 products of 20 euros the vendor fee will be (3x1 euro)+(3x20x10%) = 9 euros

But if the customer buys 4 products of 20 euros, I would like the vendor fee to be 10 euros ( the maximum cap ) instead of 12 euros (calculated)

How can this be achieved?

Many thanks