2 centenarian + partakers, older than "Frederick the great" Franz (quoting D. Splane), overlapping by 20 years each. . 201- (2x20) =161 + 1914 = 2075, plenty of time to age whiskey, and raise a glass to the centennial.
I don't think it comes down to two centenarians. You must make plans, take action before then to keep all the fish on the line. I believe by 2030 we have a revision of 1914/Generation to extend the timeline further, irrespective of "2075"
I've posted my math here before:
Franz died at 99 in 1992. Kenneth Cook graduated HS in 1980 (17 years old) That makes him 29 at Franz death. That makes him 59 today. By early 2030s he's 70. He is much closer to death and we are very far from 2075. They will be forced to re-examine their "prophecy"
(Your math may be rough for conversation only, but you cant just subtract 20 year overlap. They need to be annointed AND overlap. The likelihood that a 20yo is anointed is low. In my example with Cook, you'll note the intervening 12 years between baptism and Franz death.)