Group Discount with Taxable AND non-taxable products

[mrkrinkle]

I have a brand new 1.3.5 installation set up specifically to test this discount issue.

I am trying to work out how ZenCart handles a discount where there is taxable and nontaxable items in the cart.

My order total order is as follows;

Sub-Total ot_subtotal 100
Shipping ot_shipping 200
Discount Coupon ot_coupon 280
Group Discount ot_group_pricing 290
Tax ot_tax 300
Gift Certificates ot_gv 840
Total ot_total 999

My Group Discount settings in Order Total are;

This module is installed
true
Sort Order
290
Include Shipping
false
Include Tax
false
Re-calculate Tax
Standard
Tax Class
--none--


Purchasing these products;

$10.00 Non Taxable Product
$4.00 Taxable Product (10%)

With NO shipping I got the following results;

$14.00 Subtotal
-$1.40 Group Disount (10%)
$0.26 Tax
$12.86

This appears straight forward. The discount of $1.40 came off the taxable item (= $2.60), * 10% = $0.26 tax. My second test confirmed this theory;

$14.00 Subtotal
-$3.50 Group Disount (25%)
$0.05 Tax
$10.55

However when the discount is larger than the value of the taxable item ($4) what happens??

$14.00 Subtotal
-$7.00 Group Disount (50%)
$0.00 Tax (was not listed)
$6.70 ??? Where did this come from

Can enybody help??

[swguy]

The quantity discount contribution uses more or less the same methodology for tax preparation, and it does have flaws. If you look at

http://www.thatsoftwareguy.com/zenca...discounts.html

and scroll down to "sales tax" I give a lot of examples and explain why this is.

(Bottom line: no matter how you decide to do it, you have to make an arbitrary decision, at least
in some cases; so one arbitrary decision is made for all cases.)

Your best bet with an offering set that includes non-taxable and taxable is to use re-calculate tax=no and include tax=false. This will make the customer pay the pre-discount tax on his purchases, but the tax calculation is correct.

Good luck,
Scott

[mrkrinkle]

Thanks for your advise Scott...

So it's basically just a bug then?

Has anybody else had the same problem and devised a workaround apart from just ignoring the discount when it come to tax?

Cheers
Will

[swguy]

I wouldn't really call it a bug. It's a design compromise that I think is generally workable, although admittedly it does cause problems for people with a product mix like yours.

Have you tried using re-calculate tax = none and include tax = false? It's a common solution for bricks and mortar retailers.

Good luck,
Scott