flexi cart - A comprehensive shopping cart library for CodeIgniter

[eluser]haseydesign[/eluser]
@koichirose

The line you are probably after is @ flexi_cart_model.php:259.
This line changes the item price to a 2 decimal number, however, you can change this to 3 decimals simply by changing the code as shown below.

Code:

$item_price = $this->format_calculation($item_data[$this->flexi->cart_columns['item_price']], 3, TRUE);

From my quick testing of your example, this does result in a total of 29.99 - so maybe this will help you out?