A few of the main time/date calendar settings are on a configuration page. It looks like Minimum Booking Lead Time was updated to 2 days from 3.
Changing lead times based on instructor name or class is a big variance in how it works currently. Not saying it is not possible but it needs to be well thought out. You need to be sure you are not creating a new problem.
Besides, changing the lead time does nothing to solve our problem of needing more specific basics classes.