Coupon Not Deducting Correct Amount

[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.