Definition of the format used to represent dates (OCYYDDD+) for SMF.
The numbers are written in +ve byte packed decimal.
'0C' is the number of centuries since 1900. All dates in the 21st century have '01'.
'YY' is the year.
'DDD' is the day of the year. The first day of the year is '1' and the last day of the year '366'.
'+' is hard coded as 0xC.
10 January 2007 = 0x0107010C
1 January 2001 = 0x0101001C
31December 2012 = 0x0112366C