There are very few things the Supreme Commander can do that the Grandmaster cannot. In Silence, the Grandmaster is like the Vice President and is the only one who could rub shoulders with the Supreme Commander.
However, this does not mean that the Grandmaster and the Supreme Commander are equals, as the latter remains the more powerful of the two. He also remains the final decision maker of the organization.
The Supreme Commander has a lot of people working under him but does not necessarily work directly with them. The same goes for the Grandmaster who works more with the Masters of various fields who come directly after him.
Beneath the masters are the Team Leaders like the Personnel Manager, who are tasked to perform specific tasks. Members of Silence move up the hierarchy by proving themselves worthy of higher positions. As a result, those who matter in the organization have various people outside that they work with to achieve various fits.
