Calculate Tax based on custom price

-- url of the page with the problem -- : cdl.joomlademos.co.uk
-- HikaShop version -- : Hikashop Business 2.6.3
-- Joomla version -- : 3.6.2
-- PHP version -- : 5.6

Hey

I get my prices from an external matrix that generates the prices based on options chosen.

When I get to checkout, the Tax is calculated by the price I set for each product in Hikashop and not by the subtotal amount

See attached - the subtotal is £102 and the tax is set to 20% which should result in £20.4 in tax but Hikashop is using the price I gave to the product (in that cas Flyer which is set to £30) and calculates 2 x Flyer = £60 therefore tax is £12

How can I set the tax to be based on the subtotal number?

Thanks

Hello,

Firstly, can you give us more details about the way your products prices are set based on options chosen ? Did you use a plugin to do that ?

Thank you.