Confused about payment plans for a smaller flat

Visited some Unitech projects in Nai Basti Dundahera last week. Kids have moved out, so I need a smaller, manageable 2BHK. Builders are really pushing construction-linked payment plans. Not sure if that's smarter than a bigger down payment, especially with my old house resale pending. Should I push for different terms? What's been your experience with these plans in Ghaziabad?