Apply Discount After Taxes config not working

-- HikaShop version -- : HikaShop Business: 2.3.2
-- Joomla version -- : 3.3.3
-- PHP version -- : 5.3 (dev server)
-- Browser(s) name and version -- : All
-- Error-message(debug-mod must be tuned on) -- : Website is in offline mode during development. I am attaching screenshots of the problem.

Our client offers employer-subsidized healthcare items, vitamins, etc. The employer pays 80% of the retail cost of the products. Their employees (the store customers) must pay the full amount of taxes, calculated on the retail price.

Not all products are subsidized, so we can't simply do a discount at checkout, it must be by product category.

So we need to configure this for example:
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Retail price = $11.70 each
Tax (8%) = $0.94
Less 80% discount on retail price = -$9.36 each
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Final price of the item = $2.34 each
Taxes based on retail, before discount = $0.94
Total paid by customer at checkout = $3.28 each
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In summary, what we need is Retail Price + (Retail Price x Tax) - (Retail Price x Discount) = Final price
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What we are getting in the checkout, however, is
Retail Price + [(Retail Price - Discount) x Tax] = Final price

We have a test product set up (see screenshots) that shows the full retail and the discounted price, and you can see with the math in the checkout that discounts are being applied differently than what we are trying to achieve.

How can this be done, so we will get Retail Price + (Retail Price x Tax) - (Retail Price x Discount) = Final price ?