Sound level, Room 9 meters high outlet 7.5 mts above floor

Hello,

I have the next situation,

I have a room 8 meter height with a platform at 5.6 mts above the floor  and a few outlets place at 7.5 meter above the floor, as you can see in the inserted sketch.

-When I try to estimate the sound level above the platform changing the distance above the floor in the Acoustic data of the room, HEVACOMP says  Unacceptable value entered, permitted range 0 to 5'. 

- Changing the distance above the floor in this range( 0-50, only change the figure in the extract of my system ( placed below 5 mtos height) as you can see in the inserted pic.

I would like to get a good approximation the sound level in this platform.

I don't know  if that means HEVACOMP doesn't compute the sound over 5 meter above the floor.

Thanks in advance