Is there a way to capture if the user selects Yes/No from this menu after the Need By or Ship By dates have changed on the Order Header? From what I’ve seen, its happening in the Base Method and not calling another method according to my stack trace.

Check the Inputs/outputs for that base method. I bet there’s an output from the method that holds this value. If not, perhaps in the temp table there is a value (in the method directive, not the data directive).