Monday through Sunday on Domino's flier - isn't that like a week?

Domino's Pizza sent me a flier by mail -- see thumbnail. And I had to do a double take.

Isn't Monday through Sunday a full week? They threw my whole concept of the calendar into a state of confusion. Why didn't they just say "everyday?" Furthermore, my calendar week always starts on Sunday, not Monday. Finally, the time span appears to cover a full week, and while it says, "Limited Time Offer," nowhere on it does it say when the offer expires. We have to assume it expires at the end of a Sunday, but which one?

Anyway, it left me scratching my head.