Hi all,

Really sorry to post this again from e/where on the forum. http://www.zen-cart.com/forum/showthread.php?t=119602
It strikes me as an issue with the way tax is handled, but I need a view from a proper coder, as this facility is vital to my business. I'm sure it only requires a small alteration, but I'm struggling to find an answer:

I have a problem with group pricing and shipping (I think).
No Coupons
ZC1.3.8a
I set up a dummy product priced £100
I added it to the cart and checked out.
The cart shows:

Sub-Total: £100 (inc. VAT)

Shipping:£10.00 (inc. VAT)

Group Discount:-£5.00 (this is application of a group discount of 5%)

VAT 15%:£13.63

Total:£105.00


ot_group_pricing is set Include Shipping & Include Tax both False.

The VAT figure should be 105 * 15% = 13.70
What's actually happening is that the VAT is being calced thus:

104.50 * 15% = 13.63

The 104.50 is coming from:

100 less 5% = 95.00
10 less 5% = 9.50

The 5% is the group discount.

How do I stop the Group Discount being applied to shipping for VAT purposes? I guess it's in the tax module, but that code is a bit scary to a noob. Any help very much appreciated.

Thanks,

Sean