Winnie08:It should be the secondary school that proposes to MOE and then MOE will look at their plans and approve it.
just to share since my older DD is in RGS. Nationally, since there are fewer and fewer students in each cohort, this also affects numbers each school can take. (I don't mean through DSA but overall). Her cohort had one less class than previous cohort.
RGS just went through an exericse, including consultation with many groups, before deciding to trim/ merge some CCAs, including a couple of sports. I don't know if these sports had DSA route but i figure this is one example of how schools do have to tweak their DSA priorities from year to year.