If you give the NRO the ability to put 14,000 kilogram satellites in orbit they will certainly use it. Even if most of the extra mass is extra propellant for orbit-maintenance ion or hall effect thrusters. A lot of "big satellite" applications that use buses the size of current 6500 kilogram, largest possible telecom satellites, would be very happy to have a few thousand kj of extra propellant tanks available for the same launch cost.