Printful WooCommerce Flat rate shipping

Printful adds separate packages for printful items vs non-printful items within an order. This is helpful; however, we are using flat rate shipping and we have our WooCommerce setting set to choose the most expensive flat rate option among the items. Instead of following the flat rate setting, the cart is adding separate line items per package and charging the flat rate shipping for each package, thereby overcharging for shipping.

Is there some way we can get the Flat rate shipping to apply to the whole order?

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