Coupon Not Deducting Correct Amount

[shannonphx]

While testing some features on my site, I created a coupon code for $108.00 off, (no minimum purchase) & it took $110.90 off the order, instead of $108.00. This makes no sense at all. Previous "real" orders with a % off coupon (for the same item) do calculate correctly. So, why would a specific dollar amount calculate incorrectly?
Here's what the order page says:

Sub-Total:	$73.80
Setup Fee:	$35.00
Shipping (Standard Delivery ($8.95)):	$8.95
Discount Coupon: XXXXX:	$108.00
Total:	$6.85

The math is wrong. The order total should have been $9.75.
Any ideas about what happened & how to fix it?

[Ajeh]

Could you click Reply and answer all of the questions?

What is the add on for the Setup Fee that you have listed?

Is this just a Discount Coupon that gives $108.00 off without any restrictions?

What is your shipping module that this is using?

[shannonphx]

The set up fee is for custom glassware products that require screen printing. This feature is a custom add on to my site & has never given me any problems when combined with a % off coupon.

Yes; this is a Discount Coupon is for $108.00 off with no restrictions. (This was a test transaction, which needed to be processed through PayPal, & I didn't want a large dollar amount to actually be deducted from my account, so I created this coupon strictly for test transactions.)

My shipping module is Ceon Advanced Shipper. I have it configured to offer flat-rate standard shipping for $8.95.

Shannon

[Ajeh]

Could you hit Reply and answer the questions?

[shannonphx]

The set up fee is for custom glassware products that require screen printing. This feature is a custom add on to my site & has never given me any problems when combined with a % off coupon.

Yes; this is a Discount Coupon is for $108.00 off with no restrictions. (This was a test transaction, which needed to be processed through PayPal, & I didn't want a large dollar amount to actually be deducted from my account, so I created this coupon strictly for test transactions.)

My shipping module is Ceon Advanced Shipper. I have it configured to offer flat-rate standard shipping for $8.95.

Shannon

[Ajeh]

When you hit Reply, there are numerous questions under Posting Tips listed, could you please hit Reply and answer each of those questions?

[shannonphx]

Oh... THOSE questions. Sorry!

I'm using Zen Cart 1.5.0. I have never upgraded Zen Cart. The person who initially designed my website installed it for me.
MySQL Version: 5.5.37
PHP Version: 5.3.3 (Zend: 2.3.0)
My URL is: www.GottaHaveThat.com

Modules Installed:
PayPal Express Checkout
Fast & Easy Checkout
Products Quantity Discount
Magic Thumb
Image Handler
Easy Populate 4
CSS/JS Loader
Ceon Advanced Shipper
Ceon URI Mapping Manager
Google Analytics

My site is highly customized:
1. I have the ability to create dependent attributes.
2. Customer can purchase multiples of an item & choose different attributes for each one.
3. The site has 13 custom product design interfaces for various types of products, which the customer can design themselves. Interfaces are hosted by the product manufacturer & my site integrates these interfaces with my shopping cart.

Debug Log -- The last myDEBUG-adm file in my cache folder is dated May 22, 2014.

[RodG]

Here's what the order page says:

Sub-Total:	$73.80
Setup Fee:	$35.00
Shipping (Standard Delivery ($8.95)):	$8.95
Discount Coupon: XXXXX:	$108.00
Total:	$6.85

The math is wrong. The order total should have been $9.75.
Any ideas about what happened & how to fix it?

Do any of these figures include TAX? That's about the only thing that springs to my mind, even if it is a bit illogical that it only seems to be a problem when not using percentages.

It may be worthwhile creating a few dummy products with nice 'round' figures $10.00, $100.00 or whatever, with equally 'round' discounts and free postage in order to figure out if these is some kind of 'pattern' involved in the discrepancies (free postage so as to take this out of the equation completely).

There is sure to be some kind of pattern to the results given, and that pattern will usually provide a clue as to where things are going astray.

With the single example that you have provided it is little more than a guessing game.

Cheers
RodG

[shannonphx]

My site is configured to only charge tax when shipping to my state (Arizona). Since I used my credit card for this transaction, the order originally did include sales tax. So, I changed the shipping address to another state, which took the tax off the order. So, the totals do not include any tax.

I'll do some additional test transactions & see what happens. I'll post the results later today.

Shannon
www.GottaHaveThat.com

[RodG]

My site is configured to only charge tax when shipping to my state (Arizona). Since I used my credit card for this transaction, the order originally did include sales tax. So, I changed the shipping address to another state, which took the tax off the order. So, the totals do not include any tax.

Something to keep in mind here is that ZenCart doesn't base its tax on the order total.
Shipping tax, product tax, and even discount coupon taxes are all calculated independently, and considering the amounts involved in your current example it wouldn't surprise me if the discrepancy turns out to be caused by a shipping tax.

I admit that this is still nothing more than a wild guess though because there isn't enough data to come to any definitive conclusions, so while on the topic of performing additional tests, it may also be worthwhile configuring the store to show any tax amounts being applied.

Cheers
RodG