You’re wrong.
The per-screen average, even in ten theaters, is of paramount importance. It’s the only measure for determining whether a picture will go wide or not.
You extrapolate your potential wider audience based on this number. Sometimes you hit pay dirt, e.g. “The King’s Speech.” Sometimes you flame out. “Atlas Shrugged” did well in a few theaters, went into wider release, and subsequently bombed.
Whether “The Undefeated” will succeed when it goes wide, nobody knows — but so far, it has succeeded wildly — based on the per-screen average. To assert that the number is “meaningless” is simply inaccurate.
“Atlas Shrugs” came out in 300 theaters, and was the 3rd-highest per-screen average per theater. That is a “limited release” that did very well.
10 theaters is an extremely limited release, more like “show a film to your friends and family” release. It did well enough that they might get more theaters to show it, which is a great result; maybe we will all get to see it now.