Ned,
You have answered your own question in your quotes. Like Merlin and Typhoon, F35 is in production at the same time as flight testing continues. USMC (and some UK) aircrew will start training on the early production aircraft and the USMC will form squadrons in 2012/2013 - like Typhoon and Merlin they will not field front line capability and like the former aircraft it will take time to reach maturity. However, with a programme this size they need to get on with the build now to ensure there are enough airframes around to replace other aircraft as they go out of service. I am not saying it is the right way of doing things but it is the current pattern.
Who knows, we may pay off GR4s and some Typhoon early and increase the intro rate of F35 - anything is possible in this SDR (except increasing the size of our Forces!).