I think it has to do with the tie breaking rules. From a tie breaking perspective, the non-conference games (games versus the AFC) are "common games" which is near the bottom of the list. The division games are "common games" as well, but division games have a higher ranking. This why the last 2 or 3 games of the season are usually against North division foes. Most people believe the North division games are more important than the AFC or other NFC (non-North) games. The tie breaking formula weigh more toward the division games than toward the AFC games.
Two Clubs
Head-to-head (best won-lost-tied percentage in games between the clubs).
Best won-lost-tied percentage in games played within the division.
Best won-lost-tied percentage in
common games.
Best won-lost-tied percentage in games played within the conference.
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
common games.
Best net points in all games.
Best net touchdowns in all games.
Coin toss
Three or More Clubs
(Note: If two clubs remain tied after third or other clubs are eliminated during any step, tie breaker reverts to step 1 of the two-club format).
Head-to-head (best won-lost-tied percentage in games among the clubs).
Best won-lost-tied percentage in games played within the division.
Best won-lost-tied percentage in
common games.
Best won-lost-tied percentage in games played within the conference.
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
common games.
Best net points in all games.
Best net touchdowns in all games.
Coin toss
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.
Three or More Clubs
(Note: If two clubs remain tied after third or other clubs are eliminated, tie breaker reverts to step 1 of applicable two-club format.)
Apply division tie breaker to eliminate all but the highest ranked club in each division prior to proceeding to step 2. The original seeding within a division upon application of the division tie breaker remains the same for all subsequent applications of the procedure that are necessary to identify the two Wild-Card participants.
Head-to-head sweep. (Applicable only if one club has defeated each of the others or if one club has lost to each of the others.)
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 Green Man's avatar seems creepy, almost nightmare-ish