Dometic Awning Part Numbers and Changing out Arms

I can retract the awning to clear the door now by pressing the switch. But then I loose about 2 feet of awning, rolls up the valance and the accessory track is covered.

Dometics answer of changing the basement arms to standard arms is the solution. But I am still trying to determine what a 2 in the forth position of the part number means vs a 1. I think the 2 means auto dump and the 1 means not. But I haven't confirmed that yet.