One major problem with figuring out historical Jewish dates, and
therefore the end of the age dates, is that the Hebrew year is
actually not 360 days, nor is it 365 days. Every date setter forgets
this fact. The thing is every six years or so the Hebrews add a whole
month to their calendar to kinda make their 360 day calendar match the
solar year calendar.
   They did this so the times for sowing and harvest, as well as the
dates for their feasts would get further out of sync with the actual
solar calendar every year.      So, their calendar is never exact
anywhere. The other thing, in the diaspora, who decided to add what
and when? Some decades two months would be added to the calendar,
making the whole thing of trying to figure out when something actually
happened a chaotic mess.
            Maranatha, Lewis