You really think that the Administrative Office of the Supreme Court maintains the Supreme Court building and regulates the heat in the building?
You never cease to amaze me with what you think you know -- and don't.
Here is what they do, and they are not the GSA (which does do those things for the SCOTUS):
US CODE: Title 28,604. Duties of Director generally
http://www4.law.cornell.edu/uscode/html/uscode28/usc_sec_28_00000604----000-.html
Sheesh.
"necessary" pretty well covers everything doesn't it.