I think for any services with SD that is just going to happen
eventually unless LTA will want to explore getting another model
for SD, or designating the A22 over the Shitaro as the dominant SD
model to procure for bus packages in the immediate future.
There aren't enough new A22's to go around to replace retiring
old SD's or to fill in vacant slots left blank by previous SD's
redeployed to other or new services.
If LTA takes away the remaining BSEP A22's from SMRT to give to
other operators, KJDEP and WLDEP will probably have no choice but
to take in Shitaros as replacements too.
They should bring in K270UB along with E500 Mk4.