I see no conclusive evidence that OP has a demonstrated net advantage over 400m, but here's what everybody is ignoring: OP's perspective on the issue.
All the rhetoric about a level playing field is fine, but why do we have the concept at all? To let individual qualities rule the day--desire, hard work, focus, talent, strategy, whatever, so long as the victory is attributable to the individual.
People who compete, and win, understand what it means to feel good about themselves.
Those of us who don't cheat somehow, we don't cheat because we don't want to lie to ourselves.
Does OP feel that he has a net advantage over other competitors over 400m? If he does, he should withdraw voluntarily--I would, until I de-tuned my blades to the point where I didn't feel that I had any advantage.
Having a fairly high opinion of myself at my peak, I would have looked at my 45.0x, and thought that it was a world away from 43.1x, and concluded based on that difference that I did not have any unfair advantage.
OP might feel the same way--and of course, given the same blades, he has to put in work to realize any improvement, further buttressing his self-image, and further rationalizing his current performance as being due to all those individual qualities that we want to reward with victory, instead of to the blades.
It would take a very emotionally strong and intelligent person to examine themselves in this way, and to potentially pull themselves out, or decrease any advantage they felt that they had. As we all know, unfortunately, most people are not possessed of this sort of character.
I hope that OP has thought about it, and that he continues to think about it personally, and that he doesn't let the noise of sponsorships and appearance fees cloud his judgment. He just might be in the best position to decide whether or not he should compete.