Actually I think is the unsold units will be allocated to 2nd timers to ballot leh. Makes no sense to not let 2nd timers ballot if they are interested in the units that first timers dun want. But since leftover is little and 2nd timer application rate is very high, competition for the leftovers is very strong.You have just confirmed our worst nightmare.
Oh well, not easy to earn from govt twice in a lifetime, so I guess it’s fair.
I'm just theorising also since nobody really knows for sure except HDB themselves. One way to find out is to check the next sobf if the balance unsold for the project is equal to the next sobf on offer for the project.