Fumier highlighted the case of HK having more public holidays in a year, thus the discrepancy in annual leave allocation. Boy was that correct!
HK Public Holidays - See here. 15 days (I don't consider Saturdays since we don't work on Saturdays).
SG Public Holidays - See here. 11 days.
And there you have it! The real reason why Hongkongers enjoy less leave per year as compared to Singaporeans! Now as a World City we got to follow the leave standards set by the Europeans...