Splane makes special mention that Franz was baptized in 1913 so in 1914 he qualified to be considered as one of the anointed that discerned the times of the end and therefore part of the first group. Back in 1914 up to about 1935 all those baptized were considered to be anointed. I think he is making the point that those of the second group would be considered to be of that group, not when they were born or even baptized but at the time they considered themselves anointed and before the death of the last anointed person in the first group.
This wouldn't be so bad if they were just speculating once again.. It would be easy to excuse their speculation on the basis that they are just trying to maintain an urgency amongst the sheep so that they remain on the watch. But they are not merely speculating. They claim that this teaching is what Jesus meant when he said 'this generation'. Splane also lists a number of men who were and are anointed, he doesn't say that these people 'claim' to be of the anointed but states it as fact.