ask SBST 
certain areas where have certain amenities (e.g Wheelchair Assn in
Whampoa) or my guess large numbers of PIW and elderly...
so far for downtown only 7 serves orchard while 2, 12, 147 serve
chinatown, 196 serve shenton way, service 2, 7, 12, 51 serve bugis,
147 serve little india
services like 72, 76 and 198 do not serve downtown areas...
and ARBP, BRBP have no B9TLS or gotten any cameo B9TLs from BBDEP
or AMDEP
so if your wondering why 65, doesnt have perm B9TLS, its becuase of
the huge majority controlled by ARBP... why ARBP doesnt get B9TLs,
that one ask SBST...
but sv. 65 has those B10TLs already, it should be fine...