Question about 120mm M256 Tank Guns

[Marcello]

IIRC it is basically the opposite of what it is done for APCR rounds.
In the game, like in reality, kinetic round lose penetration as range increase (loss of speed due to aerodynamic drag).
While APCRs armed guns get a sabot range which is inferior to weapon range to simulate a steep reduction of performance as range increase, some modern APFSDS get a sabot range greater than weapon range to simulate the fact that drag has only a limited effect on them.