That's probably close to the truth.
That would be 12 x 5 = 60 games in division.
6 x 18 = 108 games out of division
= 168 games total
To be 162 games, we must have 3 less games against two different opponents.
Yes, if you are in the MIdwest division you play only three games against one team from the Central and only three against one team from the West - otherwise it is 12 against your division and six against everyone else.
In a 24 team league you also do not have a long stretch to start and end the season against your own division - divisional games are all mixed in with non-divisional.