I think that Rolex RSC prices are excessive... Just like they are for any Factory, whether it be auto Dealers, vacuum cleaners, or Rolls Royce Jet Engines...
But, one thing you do get at the RSC are new Rolex parts that they consider expendibles...such as Great Wheels, rotor axles, mainsprings, case tubes, pallets and balance wheels - and all parts are checked for Rolex original equipment tolerances.... When it comes back, it is as nearly as new as it can get without the entire watch being replaced as it can get..
When you use an independent, especially one who says that your 20 year old Rolex "didn't need any parts", is a watchmaker who took care, perhaps, but is only going to replace parts that are broken - but you still have those older worn "expendibles" inside - unless you pay extra for them. Also, many, many watchmakers do not completely disassemble a watch (it takes time) as it will be done with a Rolex Center or Rolex contracted watchmaker. The watch is broken down to major components and they are 'sonic cleaned', and it is reassembled..
If you have a trustworthy, Rolex trained or contracted watchmaker - who works to their standards, by all means, entrust your watch with them... You might even save some money. But, just because you get a cheap quote and somebody says "a Rolex is just like any other watch"; you are likely to get the latter...........
