In fact inconsistent with what you said you posted above from the manual:
Ships are put into this system by the player at Osaka, San Francisco, or Karachi, and bases must be specifically set to be
included in the system to receive supplies/fuel or have resources picked up.
Dili, you are discussing semantics with a lawyer of 35 years experience. I can only say that sometimes "may" means "shall", and "or" means "and", depending on context. Or, "and/or", which this context may support, given that the manual was a non technical document written by a committee that was not intended to be either transparent or precise.
I don't want to get into a spat, I'm just saying...
"You may find that having is not so nearly pleasing a thing as wanting. It is not logical, but it is often true."
- Cdr Spock