How To Based Tax On Quantity Of Item

Hello,

CS MVE allows you to tax as a % of the price or add a fixed sum ("absolute").

In Australia there are over 100 different taxes (levies) based on the agricultrual commodity being sold. Some of these are,

- applied based on quantity e.g. per egg or animal, and

- don't apply unless a minimum qty is sold (not pretty but I can set up two products, one for quanities below which the tax doesn't apply and another one for the higher quantity where the tax applies), and

- may be four decimal places (I have found how to adapt the amount of decimal places in the cs-cart documentation.)

I can't find advice on how to set a quantity based tax, is there a way? (I realise I could have the vendor calculate the tax as a % of the final price and do it that way, but I wish to offer my vendors an automated solution).