Perhaps not reading but interpretation maybe.
I think the thing here is the note - the note doesn't just refer to bottles it is cargo extinguishing! i.e. all of mel 26-23 (I think is, I was looking at our 330 MEL).
The next bit of the MEL refers to the agent bottles.
The next bit refers to squibs, and so on.
To me if the MEL says nbr installed 2, reqd 1, only agent 2 bottle may be inop (used or whatever) then no1 agents bottle must be serviceable.
It maybe worth having a chat with your maintrol, they are normally on the ball with this sort of thing as they deal with this sort of stuff all the time.
Of course we can just blame the French for writing things this way
