Adding Multiple Rental Rates to the Same Space

Mount Baker Theatre has standard rental rates setup for their spaces but their standard rate for events is 12 hours. They need to add on additional hourly rates if the event exceeds 12 hours. And, the rate does change when you go past 12 hours so they can't use a simple “per hour” rate.

What is the best way to handle this? I recommended booking the space for All Day to assign the standard rental rate and then to later add on the additional hours for the same space (will result in a double booking).

Another option was to book the space from 6a-6p for the 12-hour standard rate and then again from 6p-10p for the additional hours. However, they are worried about accidentally having something booked later that night without time for conversion, load-out, etc. For this reason, they want to keep the standard booking for All Day.