In Daniel 9 : 24-27, 70 weeks (they calculate 7 x 70 = 490 years) are prophecied between the word to rebuild Jerusalem (- 455) and the end of the time the covenant has been kept in force (baptism of Cornelius, + 36) .
From Daniel 5 : 23 - 26, they understand that there are 7 times between the fall of Jerusalem (they say - 607) and God appointing Jesus as king in 1914 : On the basis of 360 day years, They (Fred FRANZ did) calculate 7 x 360 = 2520 years. 607 + 1914 - 1 (year zero thing) = 2520. Don't ask why they switch from 360 day years to 365 day years...
If those 7 times were calculated out of 365 day years, and assuming we keep the - 607 date as the start of the period of time, we would get 7 x 365 = 2555 years, and 1914 would become 1949 (607 + 1949 - 1 = 2555) as the beginning of the last days ! and if we agree with historians who say that Jerusalem fell in - 587, the last days began in 1969...
Just add 120 years to make room for anti typical Noah's days and you expect ARMAGEDDON FOR 2089, or 2069 (about the date Issac NEWTON foresaw) if you stick to - 607.