looks like it worked. In my order email, it says this:
"Congratulations. Your purchase has qualified you for a $10 promotional credit toward the purchase of items shipped and sold by Amazon.com (certain exclusions apply, including Kindle books, MP3s, and video rentals and downloads). The promotional code will be emailed directly to your Amazon.com account within two days after your product ships once processing is complete.
Congratulations. Your purchase has qualified you for a $20 promotional credit toward the purchase of items shipped and sold by Amazon.com (certain exclusions apply, including Kindle books, MP3s, and video rentals and downloads). The promotional code will be emailed directly to your Amazon.com account within two days after your product ships once processing is complete."