Commutable trips can be created -- but only by destroying other good trips.

To create the commutable PM turn AM, other trips are affected:

- a different trip becomes an AM turn PM (which ELITT and TTGA shows to be undesirable excepting a highly desirable AUA, PUJ, or SJO overnight).
- unproductive pairings or longer pairings (more 4 days) are created to change the flow of start and release times.

Ends up with borrowing from Peter to pay Paul.