The Guidance System of the 40N6 is still unclearly. INS + ARH + IIR is hypothetical.
I believe that the big 40N6 missile only is used into collaboration with that Moscow ABM system.
The 48N6DM missile is a upgraded 48N6M missie from the older S-300PM System.
Ist probably only a missile for System-test for the S-400 system.