This post seems to be older than 1 year— so keep that in mind while reading. It might be outdated.
When a carrier on a route being compensated under the DPS standards (letters and/or flats) is required to case all or a significant portion of its DPS letters and/or flats, due to circumstances that have left all or some portion of the DPS letters and/or flats in an out of sequence condition, such as machine failure, trays being dropped and mail not properly re-sequenced, problems arising from the transporting of the mail, etc.; additional compensation must be provided.
via News Info-NRLCA.