USA shipping

Due to the new customs taxes coming into effect; and Shopify not updating their policies in time. 
I am unable to add 10% custom tax onto an order directly through Shopify. 
All US customers will receive an invoice for 10% of the purchase price, this then allows me to pay the import tax when I ship the item allowing it to process quickly through customs and with nothing additional for you to pay. 
Please pop me a message if you need anything clarifying.