[Imp]

From my quick look on SDBs seems to me
Stuff in service is for use against installations or stationary targets like say SAM sites.

The penetration is gained because the bomb aligns its body perfectly with the approach vector just before impact meaning it uses ALL the kinetic energy it is carrying.

The one for use against moving targets like armour is a different more complex beast & either isn't in service yet or has not been for that long.

In game terms its harder to distract/jam than its predecessors