Do all of the breakers serve the same piece of equipment? If so the disconnect would be required because 440 requires "a disconnect".
If not, I don't know why they are requiring a disconnect for the panelboard. The section Joe cited requires a disconnect for the A/C equipment, but the breakers can serve as the required means of disconnect just as well as the disconnect switch. There is no general requirement in 440 that the disconnect be lockable.