Navy and Marines agreed in 2011 that there would be 340 Bs and 340 Cs, 80 of the latter being USMC-badged. So officially "the details of that" were already settled.
That was before the price continued to go up and the AF Secretary made the following statement. The price goes up, the number goes down; so the price goes up and the numbers go down......
"No more money" for F-35 cost overruns: Pentagon
(Reuters) - Future cost overruns on the stealthy new F-35 Joint Strike Fighter built by Lockheed Martin Corp will reduce how many planes the U.S. military will ultimately buy, Air Force Secretary Michael Donley told a Senate committee on Tuesday.
Donley said the latest restructuring of the $382 billion program should allow the program to proceed with the "least risk," a message repeated by the Pentagon's F-35 program manager, chief weapons buyer and the Air Force acquisition chief at a separate House of Representatives subcommittee hearing........
Donley told the Senate Armed Services Committee that the F-35 program office and Lockheed had been told there was "no more money to put against contract overruns or problems." Any further cost growth would cut the total number of planes bought, he said, "because no more money is going to be migrating into this program," he said............