Smashburger Buy double burger, get chicken sandwich for $1, smoothie for $2

There are 2 deals going on for smash burger.
1. Smashburger Buy a double burger, get a chicken sandwich for $1
2. Smashburger Buy a double burger, get a smoothie for $2
Both deals end at 9/30. Although the fine print says "not valid with other offer or discount", I had the cashier applied both promotions at the same time (paid one full-price double burger only) with no problem. Ends up paying ~$12 for 2 burgers + 1 smoothie.
https://smashburger.com/