Reply To: selected time interval is different than actual reserved

Hi! I want to make consulting scheduler and try to use your plugin for that.
I make a test booking in the same arrival and departure date from 12:00 to 12:59 (one hour is a minimum session).
But in billing I see the double price and I take the confirmation mail with 12:00 to 13:59 time.

What should I do to fix that error?