After the buyer clicks the button to checkout with PayPal, the PayPal page that loads will not include the sales tax, or shipping if you have it setup. PayPal will only include this information after the buyer logs into PayPal so they can verify the location that was entered in on the cart matches what they have on file. If the buyer does not have a PayPal account, then the tax and/or shipping will be added after the buyer enters in their billing and shipping information.