Citation and Bibliography entries always use the same referencing system.

Using APA 6 in Word:
• citations with more than five authors employ the first name, then et al.
• bibliography entries with more than five authors employ the first six names, then '. . .' followed by the last name.
If that's not what you're getting, it's likely you're inputting them incorrectly. the correct input format is:
Author1, P J; Author2, J B; Author3, M M


where Author1, Author2, & Author3 are surnames and the letters following are their initials. Each entry is separated by a semi-colon.

__________________
Cheers,
Paul Edstein
[Fmr MS MVP - Word]