You're overreacting for an insignificant matter. As I already said that 6th gcd is a non heated split shot with the barrel off penalty. This means it's only a 160 potency weaponskill while the average potency of the other weaponskills you use during wildfire is close to 300. This is ignoring richochet, gauss round and the fact that you have a sure crit thanks to reassemble. The difference is minuscule and it only applies to the very first wildfire since you won't have fey wind after that anyway, and you won't have it even there if you don't have a sch in your party. You'd be gaining 40 potency in your first wildfire session only when a wildfire session is around 3500 total base potency. No big deal. I don't even know if that'd account for 5 more dps by the end of the fight...
Oh, and of course this isn't even remotely comparable to how much mudra lag affects nin dps for those players with very high ping (150+ ms).