The two sites I checked don't support the thesis that division records are used to determine playoff seeding between non-division opponents.
The first (
http://home.earthlink.net/~ob1gui/nflrules.htm) states that wild-card tie-breaker rules apply to determine playoff seeding. Those rules are as follows:
OTHER TIE-BREAKING PROCEDURES
Only one club advances to the playoffs in any tie-breaking step. Remaining tied clubs revert to the first step of the applicable division or Wild-Card tie breakers. As an example, if two clubs remain tied in any tie-breaker step after all other clubs have been eliminated, the procedure reverts to step one of the two-club format to determine the winner. When one club wins the tie breaker, all other clubs revert to step 1 of the applicable two-club or three-club format.
In comparing division and conference records or records against common opponents among tied teams, the best won-lost-tied percentage is the deciding factor since teams may have played an unequal number of games.
To determine home-field priority among division titlists, apply Wild-Card tie breakers.
TO BREAK A TIE FOR THE WILD-CARD TEAM
If it is necessary to break ties to determine the two Wild-Card clubs from each conference, the following steps will be taken.
If the tied clubs are from the same division, apply division tie breaker.
If the tied clubs are from different divisions, apply the following steps.
Two Clubs
Head-to-head, if applicable.
Best won-lost-tied percentage in games played within the conference.
Best won-lost-tied percentage in common games, minimum of four.
Strength of victory.
Strength of schedule.
Best combined ranking among conference teams in points scored and points allowed.
Best combined ranking among all teams in points scored and points allowed.
Best net points in conference games.
Best net points in all games.
Best net touchdowns in all games.
Coin toss.
The other, wikipedia (
http://en.wikipedia.org/wiki/NFL_playoffs), supports the first.
"The rules below are applied in order until the tie is broken. If three teams are tied for one playoff spot, the rules are applied only until the first team qualifies. If multiple playoff spots are at stake, the rules are applied in order until the first team qualifies, then the process is started again for the remaining teams.[1]
Head-to-head (team with the best record in all games played between the teams tied)
Best won-lost-tied percentage in games played within the division. (This is for determining Division Champion; also, if there is a tie for a wild-card berth, this is used for breaking ties within a division.)"
It appears to me that division records only apply to breaking ties between teams within the same division.
