Tony,

The Lord led us down the same path, but as I was going through the numbers in my head before I went to sleep for the night it made sense.  Then I woke up in the morning and went to my computer. (I even used the 1/21 date as well!)

So: without computer:
Jan 21, 2009-Aug 2012  = 42 month + a few days (so not 43 months)

But this threw me off:

From and including: Wednesday, January 21, 2009
To, but not including : Friday, August 3, 2012

It is 1290 days from the start date to the end date, but not including the end date

Or 3 years, 6 months, 13 days excluding the end date

What happened on this date to cause the abomination????  This is what is unclear.

Now, here's 1335 days, just like you said:

Yom Teruah, or Rosh Hashanah:

Duration calculation results

From and including: Wednesday, January 21, 2009
To, but not including : Monday, September 17, 2012

It is 1335 days from the start date to the end date, but not including the end date

Or 3 years, 7 months, 27 days excluding the end date