In my case I was using a bow that is about 3/8" outside of center. I think it is possible that an arrow that recovers quicker can maintain its speed better. The first time that I played with excessive fletching years ago, I made a variety spirals doing the ancient thread fletching technique, then shot them out of my Black Widow metal handled takedown with four sight pins. I was surprised how little the fletching mattered. When I made some four fletch super spiral fletched arrows, it made a few yards difference at 45 yards, but that fletching went 180 degrees around the shaft. A four yard difference from exact pin placement is not exactly falling from the sky like a lead balloon. When I tested those same arrow with that same form and bow, well over 60 yards, the difference was much more noticeable. I expected the 60 degree spin to show up with my 35 yard pin, it did not. Again, it may be just my set up, but i think 4" four fletch comes cleaner out my bows without needing to do any nock rotation tricks that 3 by 5". Even though many 4" feathers are a slighter profile than 5", I believe that the four fletch with 4" still has more feather surface area.