Apologies, are u and your friend for the same flat type in the SAME BTO?
If the 5x is for something different from your 11x flat type, then this simplistic model wont hold.
But, if you case is for same flat type in same BTO, that means, there was an assumption that I didn't take into account that since there are 5 BTOs running at the same time too, they might actually take a slower pace in the beginning, ie q no 1 to 1xx or so, like someone else, I think it was Noel13, indicated earlier. Or the 30 appts/day assumption maybe wrong in the beginning (initial) batches, which means they do about 1/2 maybe 15 +/-, and for each flat type in each BTO maybe 3-4 appts, then your 2 week difference from 5x to 11x will hold true.
If it is mid Jan for 5x, and if they started Jan 2, and mid Jan is about 2 weeks from then and 11x is about 50+ q numbers a way which is 2 weeks after 5x, then it is reasonable that they are running slow and a good assumption, this is what is happening.
Based on this data, which is only valid for CCK and Bedok, and esp those who have not heard or got any selection dates, that means their BTO selection start dates may have been push out a little and should have their dates later than 5x and 11x......yet another assumption....!!
Till we have some more good data points, then we can make a good estimate of when our appts should be.
Thx for the heads up....