Follow me here now: The HDDR shows are at 4pm, 615pm, and 830pm.
Give them 90 minutes for each show and then 30 minutes to clear the room and prep the tables for the next show. And give them 15 minutes to get the guests for the next show in the door and to their seats.
So 4pm show starts with 15 minutes of seating then show starts at 415pm for 90 minutes, ends at 545pm, clear tables and start seating again at 615pm, show starts at 630 pm and runs till 8pm.
Do it all over again - clear tables and start seating at 830pm, show starts at 845pm and runs 90 minutes.
The team of actors, servers, hosts, and kitchen staff have been running on this schedule for LITERALLY decades. They can do the schedule and routine in their sleep.
So your 830pm show with 15 minutes seating time will end in 90 minutes right at 1015pm within less than 5 minutes plus or minus. Thus to answer your original question, it will let out at 1015pm.
Bama Ed