Originally posted by ^tamago^
tat is cos sometimes it is obvious to bus fans which are their perm
svcs tat they dun really post the perm svc anymore.
for e.g., 1741P on sv 16 (which is fully controlled by ARBP), but
it is actually a spare bus from ARBP. and so on.
when u have understood enough, u will know how to read between
these lines.
actually, i merely made a factual observation (that is, people
post plate numbers followed by service route numbers)......while
you prefer to read more than what i have explicitly said.
to interpret anything more is just an active imagination. 
finally, there are many bus fans here...some will know more than
others, but no one knows everything. nothing is permanent, and to
presume that things will remain the same day-to-day is fallacious.
same goes for specific buses on "perm svcs". 
