There is some interesting logic in what the USAF are saying, we need F35 to replace one for one all sorts of different types of aircraft, including A10s, then to fund the over budget F35 development costs we want to annoy Congress by suggesting that we will take out of service the A10, implicitly shrinking the USAF and its footprint in a number of states. There is an implication that they may want to expand aircraft numbers later, if the final procurement numbers for F35As are to be achieved.
Or is the USAF saying, not yet publicly, that the final procurement number is being reduced as there will not be so many squadrons to re equip and in any case the budget has been sequestrated again? So the unit price will continue to rise. Interesting times.