Let me take back what I wrote.
what I saw in the morning was probably a one-time re-deployment,
or there is only one to two single Ds, among so many double Ds.
just now when I came back home, I kept a look out for single Ds
256 and possible single Ds sighting on 258, while at the bus
interchange and on 243G.
only saw one double D on 256, and many double Ds on 258.
more days of observations required before I know whether or not
there are really single Ds on 256.
as usual, 243G had long queues. 258 really needs those double
Ds. It is not likely that 258 would be downgraded. Besides, LTA
buses cannot be re-deployed.
(In fact, considering how much over-subscribed 243G and 242 can
be, I feel that there should really be some kind of re-organisation
of feeder routes in Jurong West Extension town...)
Speaking of which, it seems that many/all non-LTA wrights have
been re-deployed away from 243G/W. Suddenly, there are so many old
double Ds on 243G/W. :/