Last year, housing contracts needed to be in right after the May 1st deadline to accept the admission offer. Housing assignments didn’t come out until July.
Purdue moved to a system where you no longer choose an actual dorm, but only the room type. For example, a double with A/C. You pick your top three room types, fill out a housing questionnaire and then wait until the summer. From what I gathered on the parent FB page, getting your first choice room type had nothing to do with how early the housing contract was submitted.
I also believe you can’t do the housing contract without accepting your offer which required a non refundable deposit.