It is interesting to me how often Watchtower "bible-based chronology" has had 100-year "patches" applied to it, as shown by this:
"In this chapter we present the Bible evidence which indicates that six thousand years from the creation of Adam were complete with A.D. 1872; and hence that, since A.D. 1872 are chronologically entered upon the seventh thousand or the Millennium." (Studies in the Scriptures, Vol. 2, p. 33, 1889)
Watchtower Time Patches come in sizes of 40 years, 50 years, and 100 years, to name a few. Collect 'em all!