@tonypa - no. They will honor both deadlines and if your application qualifies you for your first choice they will place you there even if you apply by Jan. 1. If it doesn’t and you apply by Nov. 1 - they will defer you and review again for a March decision. If you apply by Nov. 1 or Jan. 1 and your application doesn’t qualify you for first or 2nd choice, you will be waitlisted. Deferral or waitlist shouldn’t depend on timing as much as the quality of your application.
There will be plenty of kids applying to CSE by Jan. 1 who didn’t get into their first choice (like ED for NU or CMU) for engineering. Those kids, if their stats place them in the mid 50% range for CSE, will get in. Conversely, someone with a 28 ACT who applied in Sept. may be on hold. Such is the decision process. If they went by first-come-first served, CSE/CBS/CSOM would be filled up by Oct. 1.