Not really...
According to Service 133 permanent buses list, there are
1. SBS 9033 Y
2. SBS 9047 H
3. SBS 9134 P
4. SBS 9195 M
5. SBS 9839 P
6. SBS 9840 J
7. SBS 9841G
Since a year or 2 ago, Service 133 has been maintaining the
permanent fleet of 7 double decker buses.
The reason why you have an illusion why S133 has lesser double
decker in the morning is because most of them do S133 in the early
part of the morning, and most of the single decker do the later
part of the morning.
FYI, S133 has 11 permanent single deck buses.
In the evening, there should be 3 units doing downroute, ie Suntec
City to Ang Mo Kio.
