Anator, I would preface any answer to a question about the teachings of the Watchtower with the understanding that everything they have predicted and most things they've said has proved to be completely worthless.
About the only thing they have taught that is spot on is that religion is a snare and a racket...and they should know!
I'd say the reason they need to dance around the subject of 1914 is as you have already hinted at; it is a diversion. It is to direct minds away from a disastrous eighty years of false prophecy that the generation who saw 1914 would see the end of the "old system of things." The enormity of this delusion is hard to digest. It is a total damning of their ability to claim that they are the exclusive agents of God.
"Overlapping" is a truly pathetic piece of first aid, like putting a sticking plaster on after a decapitation.
Wakey wakey Jehovah's Witnesses!