How to know how the subkeyword MDMFJI generates the values for unique Mail.dat Job IDs using MailStream Plus

Products affected:  MailStream Plus™
The first field in every record of every Mail.dat file is the 8-byte Job ID.  It is an alpha-numeric field, and per the Idealliance Mail.dat Standards-  "Job IDs are user managed, but must remain unique within one User License Code."
The fields are HDR-1001, SEG-1001, CSM-1001, etc.  (The Job ID also goes into the HDR-1153 "Historical Job ID" field.)

If a MailStream Plus job contains an RP INF with subkeyword MDMFJI and a value is given, that value will be used for the Job ID. 
If there is no RP INF MDMFJI in the job, or if there is one but no value to use is given, then MailStream Plus will generate one, in the following manner.  

The first 6 bytes are for the date and time. 
-  The first character is the year.
-  The next digit is the month, followed by day, hour, minute, and second. 

The last 2 digits are just random.
If any digit goes beyond 0 to 9, then letters are used.  For example, if the month is October, which would be 10, then the letter A is used.  Sort of like base-16. 
But this uses the numbers, upper case letters, and lower case letters.  For a total number of usable codes of 62.  The minutes or seconds go to 60. The random codes go to 62.
The only exception is the year.  It only goes from 0 to 9 using the 'ones' digit, then starts over at 0.  2010=0, 2017=7, etc.
UPDATED:  July 14, 2017