Final Round gives you NO UNFAIR ADVANTAGE. People who dump ammo to abuse it are throwing away possible kills. So while they're taking you out with one shot, which is already common with snipers because of headshots, they had to throw away 1-3 potential kills worth of ammo. All it really does is give you leeway to miss the head and still get the kill from a body shot. It may as well be Mulligan, because they're essentially the same perk.