This was something that stuck out in my head when I was studying (but obviously I never questioned it).
It never made sense to me that an all-knowing God would have to make an 'inspection' of an organization in 1918 which would determine the outcome of several billion people almost a century later. Also, you would think that such a 'prophecy' would be easily understood by reading the bible alone. Not so; I had to read many Org publications on the subject before I could get a handle on how they got to that date.