Sorry for writing in English, even if I can read Norwegian I would not be able to write properly.
There are two solutions for this question:
1. Ignore it.
2. collection_times="Days when it is emptied"
But as the mail is no longer distributed every day, this gets a bit tricky.
Check on https://www.posten.no/levering-av-post what days it is done.
Here it seems collection_times=Tu;Th would do the job.
Probably even more tricky in areas where the days change every second week.
So maybe better just stick to solution 1.