If you ran some measurements at different points in the room, you might see some different behavior. Depending on spacing and your need for both rows, you could push that back row to the wall and slide your main seats back a foot or two.
REW might give you the easiest way to measure the responses rather than going through Audyssey sessions.
Either way, I think you may benefit in the long run from getting some decorations up in there that will create natural defraction and absorption... or else some treatments... BUT! I would only do this after you have done
everything else to dial in the room.
Double checking everything from your speaker placements (pulling them in from the front corners a bit, for example) to you seating... perhaps building stands to elevate your surrounds slightly (tweeters above ear level is recommended)... basically, all the stuff that is FREE!
Once those options are exhausted, then look toward treating to solve the rest.
I'm about halfway through Master Handbook Of Acoustics Sixth Ed. and just finished the absorption chapter. Learning about this stuff is important, and I have a much greater understanding now of why its a bad idea to just start throwing panels up because you were told to treat your room.
I've seen some very experienced HT cats say they treated their rooms for years, only to find greater happiness and enjoyment after removing most of it!
Now... refresh my memory... didn't you have the room that was long and narrow, with your gear set up on the long wall, and MA Subs?