clean your track ends real good, sometimes they get some crud and grease in there and the track nuts will slide a bit. I would tend to agree that if you are running your chain that right you are probably stretching your chain and I would suggest you start running with some slack, as said before you will notice the speed increase, it's like riding 10psi low with a tight chain. But check for crap in your ends and make sure your nuts are in decent shape. Also if your track nuts are ones with out a floating serrated washer that can lead to slipping as the interface can actually flex some as well as destroying your track ends.