Actually, I already have an update!
It seems like the two additional frequencies listed are secondary frequencies. They are used as backups when the primary frequencies are not usable due to various circumstances.
If the secondary frequencies are to be used, that will indicated in the airport NOTAM.
We should improve the UI to either hide these frequencies or indicate their “secondary” nature. I’ll add that to our list of things to do, but in the meantime - this topic is solved!
Kind Regards,
Malte