225.39 The feeder or branch-circuit disconnecting means shall have a rating not less than the load to be supplied, determined in accordance with parts 1 and 2 of article 220 for branch circuits, parts 3 or 4 of article 220 for feeders, or part 5 of article 220 for farm loads. In no case shall the rating be lower then specified in 225.39 (A)(B)(C)(D).
(A) - One circuit Installation - does not apply to this thread
(B) - two circuit Installation - Does not apply to this thread
(C) - One Family Dwelling _ Does not apply to this thread
(D) - ALL OTHERS. For all other installations( this is us) the FEEDER or branch-circuit Disconnecting means shall have a rating of NOT less than 60 amperes.

I read this as saying that the FEEDER must be at least 60 amperes because it states the FEEDER or branch-circuit DISCONNECTING means ....
Isn't the the circuit breaker in the main panel the DISCONNECTING MEANS for this FEEDER ?