You're the one making the claim that different FBs make an audibly significant difference at the output jack, so it's your job to back it up, not mine to disprove it. All you've presented is a very flawed non repeated test that doesn't actually make your case at all because you don't understand it.
I've provided you with an example of how a neck reacts. What have you provided? You are certainly not an audio engineer.
If the neck has no effect, where do dead spots come from?