Hi Chris,
We request you to check the Parcel Packing option selected in plugin settings page.
If it is “Pack items individually”, then you have to “Pack items with weights and dimensions”.
Parcel Packing: WooForce plugin provides you three options to pack a parcel(s) as given below:
Pack Items Individually: In this option,each item in the cart is packed separately. Total Shipping cost calculated by adding shipping cost of each item. There is a single label for every item.
Note: This is the default option.
Pack into understand more in detail – http://www.wooforce.com/woocommerce-configure-box-dimensions-for-usps-shipping-method/
Weight based: In this option, weight of all the cart item is summed up and passed to get rates.
Let us know if the issue persists. We will help you.