I just hit on a possible solution: I just changed the binding of the Other field to connect it to the parent drop-down menu. So that means I have one drop-down menu and one text box with the same field (in this case CommOrgsName). I have conditional formatting set for the Other text box so that it only appears when the user selects "Other" from the drop-down menu. The user can enter their info here and then it gets converted into an extra drop-down menu item. When submitted, it places the new info in the same field with the others.
See attached image, #1 is first line item, a choice is selected from the drop-down. #2 is an additional table with "Other" selected from drop-down, conditional formatting makes Other text box appear. #3 user writes in new info. #4 once completed, the info displays as part of drop-down menu. #5 both instances appear in same Sharepoint column.
This is not perfect; the text box pulls the word "Other" from the drop-down menu and users will have to know they can overwrite this text with their own (I may alter the wording to say something like "Other - Please write in here"). But it puts the info in the column I need!