Does the USPS allow trays under 150 pieces for an Automation Letter mailing in MailStream Plus?

Products affected:  MailStream Plus™
Product Feature: Presort rules
Operating System: All Platforms
ML TYP 1 L – First Class letter
Per the piece thickness, only 126 pieces fit in a 2 foot tray. Is this ok with the USPS?
Yes.  If you have a letter piece that does not fit 150 pieces into a single 2-foot tray, that is fine as long as the total amount of pieces to a destination os 150 pieces or more.  The USPS has accommodated for this in the DMM rule below:
“DMM 235.1.4.o -
o. A “logical” presort destination represents the total number of pieces that are eligible for a specific presort level based on the required sortation, but which might not be contained in a single bundle or in a single container due to applicable preparation requirements or the size of the individual pieces.”
What this rule means is that you need at least 150 pieces to make the logical group to a destination.  Per DMM 233.5.4 – you need 150 pieces to get the rate:
“5.4 Price Application—Automation Cards and Letters
1-22-17] Automation prices apply to each piece that is sorted under 235.6.0 into the corresponding qualifying groups:
  1. Groups of 150 or more pieces in 5-digit/scheme trays qualify for the 5-digit price. Preparation to qualify for the 5-digit price is optional. Pieces placed in full AADC trays in lieu of 5-digit/scheme overflow trays under 235.6.5 are eligible for the 5-digit prices.
  2. Groups of 150 or more pieces in AADC trays qualify for the AADC price.
  3. Groups of fewer than 150 pieces in AADC origin and pieces placed in mixed AADC trays in lieu of AADC overflow trays under 235.6.5 are eligible for the AADC prices.
  4. Pieces in mixed AADC trays qualify for the mixed AADC price, except for pieces prepared under 5.4c.”
So using DMM 233.5.4.a, once you have hit the 150 piece minimum or “logical presort”  for a 5-digit/scheme destination, you can receive the rate.  Then per DMM DMM 235.1.4.o, these pieces are still eligible for this presort level even if they do not fit in a single container.
These rules are current as of Oct. 2017.
UPDATED:  October 27, 2017