The customer’s taxes will appear on orders based on a setting in the customer setup. Most customers are defaulted to Will Call which means that they are picking up at the branch. This will charge the branch's tax jurisdiction. Some customers that we always deliver to (either by Central trucks, or another common carrier including UPS) are set to None which means that the customer is charged the taxes where the goods are delivered. This method of taxing is consistent in most locations. Illinois and Missouri are a bit different, but the taxing should be handled the same way.
If a customer does not default to Will Call but is picking up the order or does default to Will Call but the order is being shipped the Disposition and Ship Via should be adjusted to align with how the transaction takes place.