Making my Appointment times correct

Hi there!
First off, I am a bit of a newbie, so I hope I am not totally missing the answer to my own question...I have been trying to figure it out! Second of all, I am definitely using this plugin for something it wasn't initially intended for, but I think I can make it work thanks to the flexibility built in. I am working up a website for a crashpad, which is basically a guesthouse for pilots. I want my calendar to have two options: Day beds, and Overnight Beds. I created two "service providers" which are named "Overnight Beds" and "Day Beds." I also have two services - "Day Beds" and "Overnight Beds" assigned to their namesake service providers. The services are set to last for 720 minutes. I set the SP "Day Beds" working hours from 8AM until 8PM, which is fine. When I make the calendar, there is only one time slot which can be chosen. Works fine! But then for the SP "Overnight Beds" I set working hours to be 12AM to 12AM with a break running from 8AM until 8PM (to prevent overnight beds being booked when day beds are running.) but when I make the calendar page and select the overnight service, it shows the whole month as being busy. I took away the break from 8AM-8PM, and now those days are available, but the times that are showing up are 12AM, 4AM, 8AM, and 12PM....I am not sure where those times came from. How can I get the settings right so that the only time "overnight beds" can have an appointment is at 8PM lasting though the night?

Sorry, this is a really over complicated sounding question, I wasn't sure how else to explain it!