You can now correctly manage origin vs designation-based taxes in Merch stores.
In origin-based states, sales tax should be collected based on where you, the seller, are located.
Destination-based sales tax is determined based on where the buyer is located. This is calculated by Printavo, behind-the-scenes using a service called TaxJar.
Both sales tax settings can be set when viewing a Merch store and clicking More Actions > Settings at the top.