Gross Price Calcuation in Product Editing Page

[RockToJade]

After installing osCommerce, I followed Peter Mosier's contribution "Canada Tax Zones Setup notes" to setup Canadian Tax. Then, I turned "Display Price with Tax" to TRUE in Admin, My Store.

 

The store's frontend dispaly the gross price with both taxes, GST & PST, correctly as I the store locates in PST zone.

 

e.g.

Net Price: $3.99

Gross Price: $4.45 (6% GST & 8% PST included)

 

However, the product editing page displays the following once the GST/HST/PST Zone selected.

e.g.

Net Price: $3.99

Gross Price $5.1072 (6% GST, 8% PST and 14% HST included)

 

This bug was reported on July 21st, 2004 (see http://www.oscommerce.com/community/bugs,1...ch,gross+price) and numerous discussion in the forum. However I cannot find the solution after a week of search.

 

I realizes this problem not only occurs in Canada, but also in EU with two tax zones. Thus I believe you may have the solution for me.

 

I'm looking for the following items:

1. the algorithm to solve the problem in PHP;

2. the PHP file that needs to be edited

 

Thank you, Grace