1. The WLDEP 811 MANs like to jump around, especially on
weekends. This probably explains why many O405 cameos occur on
weekends, especially WLDEP 176 perm O405s (like TIB476T, TIB542K, TIB544E, TIB558R and TIB559M).
2. Many spare O405s like TIB449Y, TIB523R, TIB538Z and TIB540R, always appear on 853.
Wonder why? TIB523R might be 853 perm...
3. When did you spot TIB733B on 961? It did its slot this
morning (75TQ1), so I guess you saw it after 3.30pm....
If 811's WAB is not strong in terms of demand, Most likely they
will play around with the fleets, ditto for 853.
For 853's case I seriously doubt the demand at Upp Boon Keng
road would require so many WCBs even 61 75 77 167 171 177 178 851
852 857 858 859 etc which went WAB in 2010-2013 respectively
doesn't require so much buses.