I agree that the output grouping can be a little confusing on MicroLogix controllers.
This model of MicroLogix has a mix of Relay and DC solid-state outputs. Some of the Relays have individual "common" terminals and some have grouped "common" terminals.
V AC DC 0 -> Relay -> Output 0
V AC DC 1 -> Relay -> Output 1
V DC 2 -> Transistors -> Outputs 2,3,4,5,6,7,8,9
V AC DC 3 -> Relays -> Output 10, 11
V AC DC 4 -> Relays -> Output 12, 13, 14, 15
You apply +24V DC to "V DC 2" and 0 V DC to "COM 2", and all the DC outputs on the controller are switched by transistors using that 24V DC source voltage.
The Relays can be used with any source voltage, within the groups indicated.