I have gone to implement the paypal system a second time into another website and have followed original instructions about upgrading and putting the php code into the functions.php file to get the paypal surcharge included into the amount.
Before I put this code in the system was working fine but now when I click 'confirm' to go through to paypal it comes up with a paypal error which says "The link you have used to enter the PayPal system contains an incorrectly formatted item amount".
The totalling amount is correct however (2.4% + 0.30 AUD).
Any ideas? thanks for the help!