Dear John & Fellow Watchers:
In terms of precision the 2013 - 2020 scenario is a better fit than the 2012 - 2019 scenario. I found three weaknesses in the 2012 calculation; there could be more: 1) Day 2520 of the Tribulation does not equal day 2300 of the Temple duration. It is off by one day. 2) Day 1260 of the Tribulation has no particular relevance. & 3) Day 2550 of the Tribulation is on Rosh Hashanah day 2.
Please review the file in order to make your own determination.