[Q]

I did the following check in the simultaneous game I described before:
- picked a race that did not scrap (because maintenance was only about 60% of the income without AI bonus).
- lowered the maintenance limit from 80% to 10%.
- next turn this AI race scrapped a ship!

Conclusion: the maintenance limit is read during the game and low values will increase scrapping.
I do not know why values higher than 100% don't work, but it might be a hard coded limit.