Of course, there must have been a thousand threads on this debate.
Having read a few of them, I say who cares? Particularly, the Society? OK, so lets say it really was 21 years later than they thought...but using their same (flawed) chronology theory:
Lets see: Jesus invisible rule: 1935 vs 1914. So what? It's still invisible - WW1 didn't end up in Armageddon anyway, and the Judge could get credit for Jesus invisible rule happening on his watch.
Further, I guess that would put out 1975 (last 1000 years of creative day) out to - 1996... So what? Nothing much happened in 1975 anyway- at least it would give you a few more years on the how long was Adam in the Garden before he noticed Eve was in the buff-- you already gave up on the "generation aware of the goings on in 1914" anyway.
My point here is - exactly what GRAND RELIGIOUS TRADITION is really tied to this date? They don't seem to have flinched on moving dates around in the past.
Maybe they just didn't want that young whippersnapper Ray Franz telling them what to do.