VERIFIED SOLUTION i

How to use the MailStream Plus ML MIN parameter to control if a mailing qualifies for presort rates.

MailStream Plus - all versions, all platforms
 
Note: by default MailStream Plus™ (MSP) uses the USPS regulations per the Domestic Mail Manual (DMM) to determine if a mailing will qualify for Presort Rates or not.  Using ML MIN to over-ride the USPS values will affect whether MSP assigns the correct rates and performs the correct presort for a mailing. 

The ML MIN parameter allows you to modify the USPS minimums required for a mailing to qualify for presort rates.
For example- 
For First-Class mail, the USPS rules are that there must be a minimum of 500 mail pieces in a mailing. 
For USPS Marketing Mail (formerly called 'Standard Mail') there must be 200 mail pieces *or* 50 pounds.

If a First-Class mailing had over 500 pieces, but the mailer wanted it to not qualify and instead go as Single-Piece rate, then ML MIN could be used to increase the minimum number of pieces required.  
Of if the Mailing was under 500 pieces, ML MIN could be used to have the mailing qualify at a lesser number of pieces.

Since USPS Marketing Mail can qualify based on number of pieces *or* weight, if a mailer wanted a normally qualifying USPS Marketing Mail mailing to not qualify, ML MIN could be used to increase both the minimum number of pieces *and* minimum required weight to large numbers to prevent the mailing from qualifying as a presort.   
Or if a mailer wanted a USPS Marketing Mail to qualify at lesser values than the defaults, ML MIN could be used to reduce the required number of pieces and/or weight needed.

ML MIN can be used similarly for other classes of mailings.

Please refer to the MSP Guide for further information on using the ML MIN parameter.
UPDATED:  March 22, 2018