Approval to charge merchant outside of the Shopify Billing API

How do apps like ShipStation gain approval to charge merchants outside of the Shopify Billing API?

This is a checkbox in the app listing when submitting for review:

Our app is for existing ShipAware users to import their Shopify shipments, so there’s no need to charge the customer double through the Shopify Billing API.

Other than submitting a support ticket and waiting a few weeks, is there another way to gain approval? Maybe I missed it. I’ve heard app reviews can take up to 6 months, so I wish there were some way to gain external charges approval without taking an additional month.

Hi, did you ever find out a reason?