Sales Tax Shown Incorrectly But Total Correct After Coupon

[gelenbaas]

Hi,

I'm having trouble trouble-shooting this problem. You can view the live store at co-soap.com. The problem affects customers in the state of California when they enter a coupon code. You can use coupon code ARCONF if you want to test it out. While the discount is correctly calculated, the sales tax quantity does not change in the shopping cart table on the check out page. However, the total is correctly calculated with the right sales tax although the wrong tax is displayed.

For example:
Prior to entering the discount code here is an order:
Sub-Total: $113.50
You Qualified for Free Shipping! (USPS Ground - Free Shipping):$0.00
California Sales Tax 7.25%:$8.23
Alameda County Sales Tax 1.5% (If in Alameda County):$1.70
Total:$123.43

After Entering the Coupon Code:
Sub-Total: $113.50
You Qualified for Free Shipping! (USPS Ground - Free Shipping):$0.00
California Sales Tax 7.25%:$8.23
Alameda County Sales Tax 1.5% (If in Alameda County):$1.70
Discount Coupon: ARCONF :-$22.70
Total:$98.75

The correct sales tax is applied even though the number displayed is incorrect, That is:
113.5 - 22.70 = 90.8. and 90.8 * 1.0875 = 98.75 with sales tax being 7.95.

I had to put the discount coupon after sales tax in the sort order of the order total module because the discount coupon was not being correctly applied.

I have the following mods installed:
Local Sales Tax Mod
Reover Cart Sales
SiteXML
SEO URLS
COWOA
FEC
Google Analytics
Javascript CSS Loader

I am not sure where to start. I am looking for the template files that are responsible for showing the shopping cart on the checkout page. If anyone has any suggestions of where to begin I'd greatly appreciate it. I am php competent but I also still learning the finer things about zen cart. Thanks for your help.
v1.3.9h

[gelenbaas]

Does anyone have any ideas? Should I try a fresh install? I'm not sure if I want to go that route and I'm a bit stuck. Thank you