Taken from the DOL DAPS manual. DAPS is an online search tool that allows authorized persons access to DOL information.
PIC- Personal Identification Code. A unique code based on a person's name and date of birth that is used by DOL for record identification. The PIC is known as the Driver License, Identicard, permit or Operator's License Number (OLN).
PK you are correct that officers and dispatchers often refer to the PIC as the last five. However, the entire sequence which includes the last five of your last name and first and middle initial are part of the PIC. You are correct that the officer entering data onto a NOI or criminal cite would only need the last five if they didn't have the ID in front of them. Really they only need the last three if they understand the way the PIC is created.
http://dapssupport.dol.wa.gov/docs/DAPS ... ex=2&lid=y
Page 19 in the manual