What does the 'Tray Preparation Types' option do (ALG PS parameter position 16), and what do the posted values mean, using MailStream Plus

MailStream Plus™, all versions, all platforms
The ALG PS parameter position 16 selects whether MailStream Plus™ generates 'Tray Preparation Type' information.  The data goes into the Audit Trail report (REPORT AUDITTRL) and the Detail report (REPORT DETAIL).  It is under a 1-byte column that's headed "TP" like this-

The value can also be optionally posted into the Name-Address output records with POSTLB parameter positions 26-28.

The posted values mean-
P      Bundled mail within the tray.
L      Unbundled mail within the tray.
S      Separator cards used in the tray.
blank  No mail Preparation Indicator Assigned

UPDATED:  May 15, 2019