Why does "ps -l" shows one number in column "PRI" but in same time "ps -o pri" shows another number?

Issue

• Why does ps -l shows one number in column "PRI" but in same time ps -o pri shows another number? for instance:

  $ ps -elf | grep migration
  F S UID      PID PPID  C PRI  NI ADDR SZ WCHAN  STIME TTY          TIME CMD
  1 S root       3    2  0 -40   - -     0 migrat Mar28 ?        00:00:04 [migration/0]
  
  $ ps -eo pid,ni,pri,comm | grep migration
  PID NI PRI COMMAND
    3  - 139 migration/0