(Editor's Note: This story has been updated to include a statement from the Pentagon's cost assessment and program evaluation office.) The Pentagon's office for independent cost estimates has concluded the Navy's two-ship buy of the third and fourth Gerald Ford-class aircraft carriers will save $3.1 billion -- $900 million less than what the service touted last week following the contract award, a new Congressional Research Service report revealed. "The Department of Defense's Office of Cost Assessment and Program Evaluation...