Coupon applying to tax also, instead of before tax

I have a 10% coupon that supposed to discount the full order of the products and shipping. When it calculates though it is also applying 10% off on the tax. I have it set to calculate the discount before tax in the configuration but it still applies the discount to the tax. Here are my versions and settings:

Joomla: 3.6.4
AwoCoupon: 2.5.9.1
Virtuemart: 3.0.18
Rupostel One Page Checkout: 2.0.320.041116

Product unit price & subtotal price at checkout on OPC: priceWithoutTax
Coupon Price Settings on OPC: salesWithoutTax

Virtuemart Tax setting for California, US: Tax per product

Is there a setting I have misconfigured or is there something else causing the issue?

Hello,

One thing to note, is that the total discount on a percentage discount before or after tax is the same, what changes is the proportion to tax and the proportion to the products:
https://awodev.com/blog/virtuemart-coupon-error-discount-before-tax#background

So what are the actual numbers in the calculation?  If you disable opc does it calculate differently?

Actually after playing with it more and running throug hthe numbers, it appears the total on the order was correct, but the numbers leading up to that were incorrect.

I changed the tax over to Vat Tax Per Product and it was displaying the correct numbers although the tax calculated number was incorrect when a coupon discount was applied.

On my test here are the numbers that should be displayed:

Inital product price - 2395.95

2156.36 - taxable product after 10%
2304.86 - subtotal before tax
188.68 - tax amount of 8.75%
2493.54 - final

With the coupon the tax amount was showing as 187.36, as it was calculated as 10% off the tax amount of 2395.95 instead of just showing the tax amount of the discounted product price of 2156.36

I disabled one page checkout and it still had the same incorrect tax value of 187.36, but the overall order total was correct at 2493.54.

I do not understand "2304.86 - subtotal before tax", where did that amount come from?

The subtotal included the $165 shipping cost that was also discounted 10%, so $148.50 was added to the discounted product price of $2156.36

Can you run it without shipping, need to verify it is an issue with just the product and not shipping

Seems that a direct 10% off all products is calculating correctly, so my 10% off the products and shipping seems to be causing the odd calulation. I have the coupon configured as:

Coupon 1: 10% off all products if any of the certain 4 products are added to the cart
Coupon 2: 10% off shipping
Parent Coupon: Setup as auto discount of both coupons only if all apply

Ok, try injection mode:

- Go to admin->awocoupon->configuration
- in the url add "&vmx=1" and load
- you should now see the option "Use Injection Mode"
- set it to 'yes' and save
- go to awocoupon->installation check and verify it is installed

Then try the coupon again in the front end.

Turning on injection mode changed the calculations to where they are now way off, even on a basic 10% discount coupon.

Calculations after turning on injection mode:

Product: $2,395.95
Shipping: $165.00
Coupon Discount (10% off product and shipping): $-256.10
Tax 8.75%: $166.40 (should be about $201.67)
Total: $2,216.48 (should be about $2,506.52)


My 10% product coupon had the calculations of (correct):

Product: $1,295.00
10% coupon: $-129.50
Tax 8.75%: $101.98
Total: $1,267.48

After Injection Mode (wrong):

Product: $1,295.00
10% coupon: $-129.50
Tax 8.75%: $90.65
Total: $1,226.65

Hello,

No idea, would have to debug it directly.  I can do that if you can send me temp admin and ftp access.