I would have thought that the $1150 Encore price includes DC enrollment only if you buy points when you come on the Encore visit. Are you sure you get the enrollment with no further outlay? If true, I advise you to enroll. It is a good deal for you but does not make sense as a business offering, which is the reason for my skepticism.
I got a similar deal at Beach Place Towers, but I paid a bit more :annoyed: $1,599, plus 75,000 Marriott Points and free enrollment in DC. I was thinking about enrolling in order to be able to use the points rental option, so it was an easy decision. I am required to do attend the presentation and if I buy additional points (not a chance) then the $1,599 is credited towards the purchase. Membership in the DC program was immediate after the 10 day waiting period.