For service 159, I think service_238 has given you the
answer.
I would like to stress again, before determining whether a service
needs DD, you have to try out the service yourself or observe the
service before slamming down the comment. Perhaps if you say
service 161 doesn't need DD during off peak hours, I may agree.
However service 161 definitely has loads to fill up a DD during
peak hours.
Off peak loads for service 161 can be quite inconsistent, so it is
better for the DDs to stay.
As for your opinion of VSOs to be on service 74, none of the depots
controlling service 74 have VSOs. The VSOs are exclusive to East
district depots, namely BRAM, AMDEP and BNDEP.