The point is that the length of “this generation” is limited to the age of the second group of anointed. Fm.
Fischerman, David Splane discussed the age issue, and volunteered, that older anointed than Frere Frederick Franz are, and will be out there. That would include clandestine partakers like yours truly, that rubbed shoulders with him in his last decade. so,
doing the numbers again: 2 anointed, reaching the not uncommon age of 100 (we have one in our congregation) and overlapping by 20 years each ( or being age 20 in 1914), gives a length of the two overlapping groups of contemporaries as 160 years, thus reaching from 1914 to 2074 for the start of the GT, 2075 for all having occurred.
Perhaps David and you wanted to emphasize how close, soon paradise is, but end up to sink the hopes of most that are alive now, and wt sticks to its 1918/19 slogan: " millions now , in 2022, living will never die, "will not pass away"
Jesus was specific in saying that the generation will pass away, and when, ---- after the GT, not before, as wt at present prophecies.
The anointed will have to pass away to go to heaven as did the Christ. wt Mission impossible.