I am trying to display all prices with 4 decimals (i know a little bit weird but the customer demanded this). I have overwritten Mage/Core/Store, changed the currency.php precision in the Zend lib and adjusted Mage_Directory_Model_Currency.
In the backend, all my prices are displayed correctly but in the frontend i receive a price rounded to 2 decimals followed by 00. Especially the tier price is very crucial.
Since i dont have any knowledge in pricing i have tried some tutorials on Magento Forum with no success. I also tried 2 extensions with no luck.