Clementi hdb crosses 1m is because that hdb is one of its kind. You don't see a mall attached hdb. And that the bus interchange is within few footsteps, not few min walk, from the hdb lift lobbies. Of course the popularity of clementi play some part too.
Bump. The poll results thus far shows that buyers are quite ready to absorb 16xxpsf for OCR Clementi which explains Clementi popularity in terms of resale BTO too crossing 1m.