I can't be arsed to look it up, but I thought the SCC was independent?
The SCC, is IIRC guided by, but not funded, by the MOD (or not to anywhere the same extent as the ATC and ACF.)
or, to put it another way, using cliches:
The MOD funds the ACF and ATC to a higher degree, and therefore 'he who pays the piper calls the tune'
Having seen the dearth of choice offered by the baby Andrew and Baby Crabs, we get the best deal. My cadets subs are a fiver a month. The local ATC£18 and the SCC £15. On top of this their cadets have to buy various uniform items that we in the ACF issue FOC. Recently we have recruited a few ex-cadets from these local units who say that they don't do anything except bag packing to raise money for the minibus and aggressively demand subs are paid. Does that sound familiar?