Bid step and auction closing date

Hello!

Sorry I’m if not following the correct guidelines for posting an issue, I’m new to Drupal.

I wanted to ask if there’s any way to make some parameters chose by the website administrators instead of the users when they create an auction.

Example 1: is there a way to make the bid step a formula based on the current value instead of user selecting it?

Example 2: is there a way to make that all auctions will have the same duration (so the user can’t select when it closes) or instead give the user a few options like: 1 week, 2 weeks or 3 weeks instead of having complete control of the time/date?

Thanks in advance!