Hi Bill
It's in the Power Commander V software. As long as yours does Fuel & Ignition (early PCV's only did fuel) it can be turned on.
With the PCV connected to the PC if you click the menu "Power commander tools", then "configure", then "Feature enable and input selections". This will pop up screen with lots of options that can be enabled or disabled.
If you enable Rev-Xtend it will bump the limiter by 500 RPM. If you want to bump it further you need to phone Dynojet for an unlock code.
I think Farmer John is correct on my issue, looking at my ignition map it looks odd past 5k at WOT.