Shipping price increased by %, possible?

Hi guys,
i need a simple way to increase my shipping price by 10%, is this possible to setup?
i didnot find any info.
also would it be able to work only for certain shipping methods?

i am running latest version of zencart with usps and upsxml shipping modules, its a usa store.

Thanks! :clap:

You would need to customize your usps.php shipping module ...

You will see where the final price is built at:

          $methods[] = array('id' => $type,
                             'title' => $title,
                             'cost' => ($cost + MODULE_SHIPPING_USPS_HANDLING) * $shipping_num_boxes);

You didn't say -what- module you are using. Some of them allow for a handling charge to be added. Another option is to increase your tare weight so the shipping weight goes up to match your packaging.