The graph looks fine to me, especially on the second WOT pull. I wouldn't worry so much about it. I have changed my plugs, and did the walnut blasting and cylinder #5 is the only one correcting on mine. Try adding one gallon of E-85 and then top off the tank with 91-93 octane (whichever is available) and after a half tank of that re-log a few pulls and post it up. should clean up some of the other timing issues. If you don't want to run a little E-85, or don't have a station around you for it, try adding a bottle of Torco accelerator to a tank full and that will deff help things out, but we are talking mostly race day precautions on the fuels end here...
Either way I wouldnt worry so much about it.