Coupons: automatic taxes behaviour

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We enter all prices in the shop as consumer prices so including taxes (VAT) of 21%.
When I set "Apply discounts" in the configuration as "After taxes", and make a € 10 flat coupon , the following happens:
Goods subtotal: 54.74 (= 45.24 + 9.50 tax)
Freight: 9.50 (= 7.85 + 1.65 tax)
Coupon -10.00 (= 8.26 + 1.74 tax)
Total: 45.24 (correct)
Tax 9.05 This is obviously wrong, it should be 9.50 + 1.65 - 1.74 = 9.41
In the mass actions export, the "order_discount_tax" shows up as 0.

When I set Apply discounts" in the configuration as "Before taxes", it works as expexted.

How is After tax supposed to work?
Which I thought would be the consumer amount (amount after taxes has been applied).
Does anyone know?

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Hi,

Sorry, my bad! I meant to say the "Apply coupons" setting!

If that settig is set as "After taxes", the mentioned behavior occurrs.
First of all, the "order_discount_tax" field in the database is set to 0. It's also visible as 0 in the mass actions csv output.

And in the "order_full_tax", an amount of € 2.10 (€ 10 coupon * 21% vat) is being deducted.
So the sum of taxes on goods, shipping and coupons does not match anymore.
This is definitely wrong.

And there is the confusion between before and after tax.
Ussually, "After taxes" means the consumer price to which taxes have been added.

Here, at least for coupons, it seems to be the other way around. If I want to give a consumer a coupon of € 10 (so lower the consumer total invoice amount by € 10), I have set the coupon of € 10 as "Before taxes"?
But to the discounts, at least when I use it as a percentage on a product price, it works as expected when set to "After taxes" !
Could you please check and clearify?

Thanks in advance!

Hi,

Did you have a chance to look at the processing of VAT on coupons?
Thanks in advance!

Best regards,
Eric