Hehe...
Simple calculation , this is what i do
Please note the units selected & drop out is just a calculation not the actual result.
But the dates are the actual selection date & Q number
Eg NOV 2015 SOBF
Woodlands 3 room
19 units selection start 17 June 2016
Day 1 : 17 June 2016 Q2-Q6
But on that actual day 5 units selected (0 drop out)
Day 2: 20 June 2016 Q7-Q11
But on that actual day only 3 units selected (2 drop out)
Day 3: 23 June 2016 Q12-26
But on that actual day only 7 units selected (8 drop out)
Day 4: 28 June 2016 Q27-31
But on that actual day only 4 units selected (1 drop out)
By June all 19 units selected loh.
That was my actual heartache experience for SOBF NOV 2015

I practically call the hotline and ask for the dates and Q numbers for the days and every time there's a selection going on. My refresh button was super exhausted!
Haha