VAT wrong after applying Discount Coupon

I've been on this all day and can't get it to calculate correctly, could do with some inspiration.

current set up
ZC 1.301 set up for UK with VAT @ 17.5%, Display Prices with Tax is ON

Order Total:
ot_coupon 200
ot_shipping 280
ot_subtotal 100
ot_tax 900
ot_total 999

Discount Coupon
Include Shipping: False
Include Tax: True
Re-Calculate Tax: None

Checkout shows the following:

Sub-Total £1.50 <- Correct
Discount Coupon -£1.00 <- Correct
Shipping £1.00 <- Correct
VAT included in order £0.37 < Incorrect
Total £1.50 <- Correct

I've tried various permutations where I end up with the correct VAT and incorrect Total but can't get the correct solution.

From what I can see the VAT is being calculated before the Discount Coupon is applied.

I'm now guessing that I need to hack some files but don't know what to do or where.

If anyone else has a UK set up using Discount Coupons working correctly I'd be over joyed to hear you solution.

thanks for any help

Bunster

Have a look at this thread which may help you.

I can't remember the exact details but my head hurt at the time and I was getting nowhere until Jeff and Linda helped me. :thumbsup:

It might not help you but may give you some pointers. There are also a number of other threads on the topic. You'll need to search on VAT*

Thanks Brent for the reply, at least I know now that it's not just me :-)

I'll have another look through the posts ( thought I'd read them all ) and post back any solutions that work.

Bunster