The following general fixes were made to Magento tax configuration and calculations:

• Canadian customers now receive an e-mail with the correct totals for invoices and credit memos that include Provincial Sales Tax (PST) and Goods and Services Tax (GST).
• Resolved issues with incorrect prices and incorrect tax amounts when a custom price is used together with the configuration setting System >Configuration > SALES > Tax > Calculation Settings, option Apply Tax On set to Original price only.
• The tax amount is calculated correctly when:
  • The customer is in a different taxing jurisdiction than the web store
  • The configuration option System > Configuration > SALES > Tax > Calculation Settings, option Catalog Prices is set to Including Tax
  • The configuration option System > Configuration > SALES > Tax > Calculation Settings, option Tax Calculation Method Based On is set to Unit Price
• The row total including tax displayed in the shopping cart is calculated correctly when:
  • The configuration option System > Configuration > SALES > Tax > Calculation Settings, option Catalog Prices is set to Excluding Tax
  • The configuration option System > Configuration > SALES > Tax > Calculation Settings, option Tax Calculation Method Based On is set to Row Total
• The row subtotal displays the correct amount when reordering a product that includes a discount coupon.
• Multiple tax rates for a product display correctly in the Admin Panel when creating an invoice or credit memo.
• Resolved calculation errors when tax and currency conversion are applied. As a result, the price the customer views on a catalog or product page is the same as the price displayed in the shopping cart.
• A customer can now place an order when two tax rules are applied to a product, even if the tax rules specify the same tax rate.
• Resolved issues with calculating taxes on orders that are shipped to different countries that have different tax rates.
• Product prices, including taxes, display on category and product pages the same for a guest customer as for a logged-in customer. (A guest customer is a customer who does not log in to your web store; this customer belongs to the NOT LOGGED IN customer group.)

Rounding Issues

The following tax rounding issues were resolved:

• Resolved a rounding issue in the tax detail display in the shopping cart when more than one tax rule is used.
• Resolved an issue reported on stackoverflow where a calculation error resulted from the following configuration:
  System > Configuration > SALES > Tax > Calculation Settings, option Tax Calculation Method Based On set to Total
  System > Configuration > SALES > Tax > Calculation Settings, option Catalog Prices set to Including Tax
• As a result of allowing a 0% tax rate, rounding errors related to different VAT jurisdictions have been resolved. For example, if a product originates in a country with VAT but is shipped to another country that has no VAT, correct prices display in the shopping cart.
• Row totals display correctly in the shopping cart when:
  • A shopping cart discount is applied
  • The following configuration options are set in System > Configuration > SALES > Tax > Calculation Settings:
    • Catalog Prices is set to Including Tax
    • Tax Calculation Method Based On is set to Excluding Tax
    • Apply Customer Tax is set to After Discount
    • Apply Discount On Prices is set to Including Taxes