Thanks for the update!
I would write back, copy Marriott corporate office and ask why the $100 was not offered. The coupons seem like a good deal. If you use them at one of the more expensive CYs they could be worth more than double the $100 each. But Marriott needs to know that their hotel does not follow the correct procedure.
BTW - was your post a cut-and-paste of an email that was sent to you or did you re-type it? The reason I ask is the typo would be okay if you were retyping something, but would be pretty bad if it was within the actual apology sent by the hotel manager.