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MailStream Plus- Mailing (nonprofit) Parcels in Standard Mail.

In 2012, the USPS moved some types of Standard Mail 'profit' parcels to Package Services.  These are indicated by using an L (for 'Parcel Select Lightweight') in the ML TYP parameter position 12.

With few exceptions, Parcels now have to be nonprofit to be mailed as Standard Mail.  One of the exceptions are Marketing Parcels, which can be either profit or non-profit. 

Non-Profit mail pieces are indicated by a N in the P ATTR parameter position 60.  Note- if left blank, position 60 defaults to “N” for Standard Mail Parcels that are not Marketing parcels,

For additional information, see also Knowledge Base article-
"MailStream Plus- Setting up a 'Parcel Select Lightweight' mailing, which goes onto a 3605 Postage Statement."
UPDATED:  April 21, 2017