VERIFIED SOLUTION i

How to make selected input records go to single piece rate, if they have a valid ZIP Code in MailStream Plus

1)
Pieces with *invalid* ZIP Codes will be written to the reject file FILEDF MSSTOR, if a FILEDF MSSTOR parameter is in the job.  
If there is no FILEDF MSSTOR, then the pieces by default will travel along to the output file, but not be included in the presort in any way.  Although there is an option on ALG PS position 18 to put a Y which tells MailStream Plus (MSP) to process invalid ZIP Code records as single piece rate mail.

2)
Or if you wanted *all* of the pieces in a mailing to go single piece rate, even if they have valid ZIP Codes, then you could use an ML MIN parameter to specify a minimum qualifying number large enough that the mailing would not meet it.

3) 
*But* is there a way to make *some* specific pieces, with *valid* ZIP Codes, go single piece rate?  Maybe based on some value located somewhere in the records?
Not really.  There is no option specifically for that.  But there is a method-
There is an option on the ALG PS parameter position 24 to tell MSP to consider non-compliant NCOA records to be invalid.

So you could post a 'non-compliant' value '02' or '03' into the selected records.
Use the ADQUAL parameter position 40-42 to tell MSP where the value is posted (and you have to put some location value in ADQUAL positions 44-46 too.  The same location should work.)
Use ALG PS position 24 to tell MSP to consider NCOA non-compliant records invalid.  
Then you can use ALG PS position 18 to process 'non-compliant' records as single piece rate mail.
UPDATED:  April 20, 2017