When using an integrated or non-integrated shipping method setup in your Pressero account, there are fields for "Max Weight Per Package", "Handling Charge" and "Markup %" that can have values added to them.
When Pressero is calculating the cost for shipping for orders in cart, it will first use the "Max Weight Per Package" value to determine how many packages the weight in cart will break into when shipped.
The amounts specified for "Handling Charge" and "Markup %" will then be added to each package, and the total will be added to the rate being returned from the shipping provider (if using an integrated shipping method) and that will become the total shipping price for that order. If using a non-integrated shipping method, then that total will become the shipping price for the order.
For example, let us suppose you are using UPS Ground with a $1.00 "Handling Charge", a 10% "Markup %" set, a setting of 5 lbs as the "Max Weight Per Package", and that you have 20 lbs of product in the shopping cart.
The total of the weight in the shopping cart will become 4 packages, with the handling charge and markup applied to each one. If UPS returns a rate of $5 for each package, then it will be $5 + $1 * 10% = $6.60 * 4 = $26.40 for the shipping charge showing for the order in the shopping cart.