I've had a look through the forums and Zen Cart tutorials and not found the answer to my issue.

Basically I've set up perweightunit shipping option and everything works fine. The problem I have is that I want 1 charge per order so if a customer orders 3 items they are charged once at the rate of the most expensive item. At the moment it adds a charge per item.

Looking at the forums thus far I'm worried that a fix is based on editing php code, which is not something I'm overly familiar with. Any help would greatly be appreciated.

In terms of Zen Cart the store is running the latest version and has only the perweightunit shipping option enabled.