Tax Miscalculation with Discounts

[Danebrood]

It looks like when there are discounts, sales tax is being calculated a little wonky.

For example a transaction that would normally play out like:

$30 Subtotal
- $7.50 ( 25% discount coupon)
+ $5.10 Shipping

(30 - 7.50 + 5.10) = 27.60

Tax = (27.60 X 0.084) = $2.32
Total = (2.32 + 27.60) = $29.92


Is getting calculated in a strange order by zen:

$30 + $5.10 = $35.10 (subtotal + shipping)
0.084 X (1 - .25) = 0.063 (tax rate less coupon discount of 25%)
$35.10 X 1.063 = $37.31 (total X (1 + tax))
$37.31 - 7.50 = $29.81 ( total with tax minus coupon)

close, but wrong. This happens with all types of discounts.

All my discount modules are set to not include tax, and Standard tax recalculation. Store set to include shipping in the tax calculation. Tax works great when there isn't a discount occurring.

Any ideas?

[DrByte]

What version of Zen Cart are you using?
What addons do you have installed?
Which discount modules do you have enabled?
What is your URL?
What states are you collecting tax for?
What tax rates are configured in your store?

[Danebrood]

Hey there, thanks for the response.

To keep this simple, the issue can be duplicated with a default installation of v.1.3.8a using the sample products included with the installation and sample coupon.

Checkout with the coupon 'zzzz', and set your address to Florida to include tax. Here's the order total calculation I just got, shipping to Florida:

$299 Sub-Total (1 x Matrox G200 MMS)

$2.50 Per Item (Best Way)

-$45.00 Discount Coupon: zzzz

$17.85 FL TAX 7.0%

$275.34 Total


The pre-tax total is $256.50, which should result in 7% tax of $17.96.


If you need a default 1.3.8a installation, I've got one here:

http://www.indexsmithy.com/demos/zen-default/

It's nearly a pristine installation, but think I've just disabled some payment and shipping options.

[tzeyangng]

i had the similar situation. anyone found the solution to this yet?

[tzeyangng]

anyone please help? This issue has been bugging me for few days. and my store is up and running now. please help. Any help is appreciate.