Congratulations on actually doing tests to answer questions. :thumbs_up
In my own testing a few years ago, I collected random arrow, all with different length, weight, spine, fletching, etc. They were found arrows from public ranges and arrows from my clubs arrow bucket.
Up to about 20 yards the only arrow factor that made significant difference was arrow diameter. ACC's impacted low and 2613 impacted high. Everything else was in between. Of course I had to run this test quite a few times because the other factor was my shooting ability.
At longer distances, the differences became more significant, but arrow diameter was still the biggest factor.
Allen
The more precisely arrows are matched, the better. But for short range, it's not as critical.