Yes. And here's the catch. You don't get the Amex discount if you don't use dhl or FedEx. Fedex needs to have a value over $1,000 which opens you up to import duty and GSt which for many items negates the benefit from shopping overseas.
Any good alternatives as myus won't be getting any more of my business
You still get the discount for their 'trusted courier' network which is actually USPS, and at only a few dollars cheaper than the named couriers they'd be making a fair bit of margin on this method. What's wrong with DHL?