Our cart's tax settings should override any tax settings in your PayPal account, but you should probably remove any such settings at PayPal's end anyway.
Our shipping settings also should have overridden those in your PayPal profile, but our Developers have been fine-tuning our integration with PayPal's new automatic shipping recalculation feature (where they contact our system to recalculate shipping based on the actual shipping destination provided by the buyer during checkout), so we may have needed to disable that auto-override for some reason. You can enable the override manually in your PayPal profile's shipping settings by checking the option to "Allow transaction-based shipping values to override the profile shipping settings listed above (if profile settings are enabled)".