Its really simple.
Jesus (allegedly) said that some of the people who were alive right then as he was speaking would STILL be alive to witness the events leading up to Jerusalem's destruction. There was no 'NEXT' or 'OVERLAPPING' group.
Up until 1995, JW's preached that some people that were alive to witness the events of 1914 would STILL be alive to witness the destruction of this world at God's hand. There was no 'NEXT' or 'OVERLAPPING' group.
I don't want to confuse the issue but another way to look at the stupidity of the change is this; My Grandfather passed away in 1987. I was alive while my Grandfather was alive and so our lives overlapped. He witnessed world war 2 but I didn't. According to the theory that the FDS is espousing, that makes me a part of the generation that saw world war 2, even though I wasn't around to witness it.
Sound stupid?? - Yes it does.
Using their theory in the other direction of time, this also makes my Grandfather a part of the 'facebook generation'- even though he passed away 20 years before it was launched, because my life and his 'overlapped'.
I actually cant believe the FDS are getting away with this complete misinterpretation and twisting of a simple concept. They should just say they were wrong about 1914. But we know that will never happen.