The 2-pole 6-throw switch has an internal limiter so that it only turns half as far as the 1P12T version. 6 of the outputs on one side are alternately connected to one of the center pins and the 6 on the other side connect to the other center pin.
If you only need a 2P5T switch, you can put in a limit plug in the holes around the shaft to prevent it turning to the last position (or whatever number of throws you want.) They used to come with a plug but I haven't seen one in years. A piece of wire or plastic jammed in the hole works.