What is your finger position on the string? I shoot 2 under with cock feather against the riser, it works for me and I get perfect arrow flight with field points and BH's. It could be your cushion that's causing deflection? I use the soft part of Velcro on the side plate and the riser plate, cock feather in, and 2 fingers under with a finger tab on my Kodiak Super Mag, perfect flight with everything.
Check your nock point, ie up and down of the nock on the string verses the level of the arrow on the arrow shelf. Plus I use one string nock (hard nock above and below the arrow nock)
One more thing, if your arrow is slapping the riser of the bow so hard that it's tearing up your fletchings, you may be underspined? Feather fletchings are naturally made to lay flat when clearing the riser of the bow and shouldn't wear all that much if the bow is tuned properly. It's hard to diagnose a problem without putting hands on the bow itself and actually shooting it. I'd suggest using Stu's calculator and determine if your correctly spined in your arrow selection/versus point wt. ect.
Here's the link, it works!
http://heilakka.com/stumiller/ Hope that helps.