Abbildung 4-18: ZURPFKHP - Struktur HD- Pumpenelementschaltung
Very interesting, map and drawing the piston 3 is active at zuwEL_KF(16*8) > 60 % (zuwEL_on).

This definitely needs more testing, but on my car it was orginally running by 3 pistons when IQ20-30 from 0- 2500rpm. Above that 3rd piston was dropped.
So i was modified 16x8 map. Now it runs 2 pistons on those light load hiqh way situations also(1500+ it is 2 piston).
First "feelings" was positive but maybe this needs some accuracy measurement before making any real statement.
On my mind it makes sens that if not pressure or quanity is demand then only 2 pistons used.