Discount Coupon AND Group Discount Tax Problem

[mrkrinkle]

I have a problem with tax calculations where a Discount Coupon and a Group Discount apply...

Sub-Total: $10.00
Shipping Not Applicable: $0.00
Discount Coupon (25%): -$2.50
Group Discount (10%): -$0.72
GST (10%): $0.75
Total: $7.53

The GST is calculating with the Discount Coupon but not the Group Discount.

The Group Discount options are:

Include Shipping
true

Include Tax
false

Re-calculate Tax
Credit Note

Tax Class
GST

And the Discount Coupon options are;

Include Shipping
true

Include Tax
false

Re-calculate Tax
Credit Note

Tax Class
GST

Zen Cart version is 1.3.0.1.

On it's own the Group Discount works;

Sub-Total: $10.00
Shipping Not Applicable: $0.00
Group Discount (10%): -$1.00
GST (10%): $1.00
Total: $10.00

As does the Discount Coupon on it's own;

Sub-Total: $10.00
Shipping Not Applicable: $0.00
Discount Coupon (25%): -$2.50
GST (10%): $0.75
Total: $8.25

Any Clues?

[Kim]

Have you tried restoring the default settings for both modules?

[mrkrinkle]

What are the defaults?

I have tried all different combinations but I need the Discounts to be applied pre-tax...

[mrkrinkle]

I have recreated the scenario on my test site which is v1.3.0.2 and still have the sam problem...

This is what it should look like according to my calculations;

Sub-Total: $10.00
Shipping (Flat Rate): $5.00 = $15.00
Discount Coupon (10%): -$1.50 = $13.50
Group Discount (10%): -$1.35 = $12.15
GST Tax (10%): $1.21 = $13.36
Total: $13.36

As you can see below the GST Tax does not re-calculate after the Group Discount;

Sub-Total: $10.00
Shipping (Flat Rate): $5.00
Discount Coupon (10%): -$1.50
Group Discount (10%): -$1.35
GST Tax (10%): $1.35
Total: $13.50

The GST Tax and Total appear to be wrong.
If I swap the order of the Discount Coupon so it is calculated after the Group Disount I get this;

Sub-Total: $10.00
Shipping (Flat Rate): $5.00
Group Discount (10%): -$1.50
Discount Coupon (10%): -$1.50
GST Tax (10%): $1.35
Total: $13.35

The Discount Coupon, GST Tax and Total appear to be wrong although Total is only 1c out and may be rounding issue.
If I revert to either the Group Discount or Discount Coupon on their own then it works fine;

Sub-Total: $10.00
Shipping (Flat Rate): $5.00
Group Discount (10%): -$1.50
GST Tax (10%): $1.35
Total: $14.85

Sub-Total: $10.00
Shipping (Flat Rate): $5.00
Discount Coupon (10%): -$1.50
GST Tax (10%): $1.35
Total: $14.85


INFO

The Zen Cart Version is 1.3.0.2, the Shipping and product are both taxable.
Both Disount Coupon And Group Discount have the following settings;

This module is installed
true
Sort Order
280
Include Shipping
true
Include Tax
false
Re-calculate Tax
Standard
Tax Class
--none--

Can anyone help or have you had a similar issue?

Cheers
Will

[mrkrinkle]

I think I have worked out where my problems are coming from...

When you have taxable and non-taxable items and you apply a discount (Coupon or Group), does the discount subtract from the taxable item or the non-taxable or both, an if both how does it calculate the percentage. This calculation obviously effects the tax payable on the order...

Does anyone know how this works?

Cheers
Will

[DrByte]

Before pulling any more hair, you might want to fix a small bug:

includes/modules/order_total/ot_group_pricing.php
line 21 has:

      $this->credit_tax = MODULE_ORDER_TOTAL_GROUP_PRICING_CREDIT_TAX; 

change it to:

      $this->tax_class = MODULE_ORDER_TOTAL_GROUP_PRICING_TAX_CLASS; 

As an addendum, the "include shipping" and "include tax" settings, if set to "true", work like this:
"Order Total" minus "Shipping Costs" minus "Tax Amount" = "Amount to apply discount to"
ie: $50.00 - $3.50 - $2.80 = $43.70 .... if discount rate is 10%, then the discount will be $4.37

Hope that helps clarify some of how it works.

[mrkrinkle]

I don't really want to uninstall everthing at this stage as it is live however...

When you have taxable and non-taxable items and you apply a discount (Coupon or Group Discount), does the discount subtract from the taxable item or the non-taxable or both?

If both, how does it calculate the amounts to discount from the taxable and non-taxable items?


Anbody know the standard processes that applies here?

Thanks,
Will

[vinod_989]

I have a problem in tax calcluation. i have applied tax calss at each product. when i apply discount coupn then tax calculation is not correct at the puag and play payment getway .

so please suggect me the solutuion for this