Just for fun, I shot three arrows today at ranges varying from 10 yards to 40 yards, paying attention to where each arrow hit vertically.
The first arrow was my regular target longbow arrow, which weighs 421 grains, giving me just over 10 gpp in my 40# longbow. It is fletched with 3 - 4" feathers.
The second arrow is a semi flu-flu which weighs 440 grains. It is fletched with 6 - 5" feathers which are cut to a higher profile than regular 5" feathers.
The third arrow is also a semi flu-flu, which weighs 528 grains. It is also fletched with 6 - 5" feathers, but they have a normal profile for 5" feathers.
These are all wood arrows spined in the same 45-50# spine range. They all have the same points, and are all pretty straight (for wood arrows). I would assume the reason arrow #3 is so much heavier is because it is made out of heavier wood, maybe Douglas fir or something.
For all the ranges I shot, arrows #1 and #2 shot close enough together that I didn't feel like I had to adjust my aim to get them in the same group.
Arrow #3 impacted consistently lower than the other two. I would say the average POI was a couple of inches lower at 15 yards, and 8-10" lower at 40 yards.
My conclusion is that weight is far more important in determining arrow trajectory than feathers. Even though arrow #2 has higher profile feathers than the other semi flu-flu, and more than double the feather area of my regular arrows, and even though it is slightly heavier, it still impacted reasonably close to my regular arrows. Typically, if I shot 5 regular arrows at a target, arrow #2 might be low in the group, but there would be 1-2 regular arrows lower than arrow #2.
Arrow #3 would always be below a group of regular arrows, unless I just made a bad shot with one of my regular arrows.