I'm considering adding a 2nd property to my account. I'd like to know if the pricing will be per booking like my current property, or will I be switched to the flat $19.99/month price? Thanks.
Your current billing "plan" is what determines how you will be billed. If you currently have the Legacy Usage plan, then you'll continue to be billed according to that plan's pricing model. Here's a support doc about Legacy Usage pricing: