[fixed 1.3.9a] Group Discount and Discount Coupon Tax Calculation Issue

[kavlito]

After implementing Group Pricing, my tax was incorrectly calculating based on Sub-Total. I edited the Group Discount in the Order Totals Module and set Re-calculate Tax to Standard and now the tax is calculated correctly after the Group Discount is applied.

[Leijonberg]

I have a similar problem. Tax calculation is correct, even when coupons or group pricing are used. The discount displayed and the total is wrong though.

On an order value of 1995,00 (1596,00 excl. VAT), I get 224,00 discount with 10% setting (where I should get 199,50). Shipping is 118,00 (94,40 excl. VAT) and the VAT is 25%, so I get:

((1596 - 10%) + 94,4) * 0,25 = 382,7 (VAT)

This is calculated correctly (rounded to 383,00).
Order total should thus be 1913,50, but I get 1850,00 in order total.

This means that the discount I really got in the total is:

1995 + 118 - 1850 = 263,00

and not the 224,00 displayed, or the 199,50 as it should be.

Could someone please help me? Where do I look for a solution?

[coredesign]

After some fiddling around, my cart's handling of the order total, discount and tax on net order amount are working properly.

HOWEVER, I am now seeing an issue with the shipping tax calculation! The shipping amount shown on the Checkout page is correct, but the tax on shipping is being calculated on the shipping cost minus the discount coupon percentage.

Please see the attached PDF for the numbers I'm looking at.

ot_coupon
Include Shipping: false
Include Tax: false
Recalculate Tax: Standard

Display Prices with Tax: false