Who states that the KWK40 didn´t use 75mm K.Gr.rot Pz. during 1942 (before the widespread service advent of the 75mm Pzgr.39), which in british terminology is a 75mm A.P.C.H.E.?
Notice, that Pzgr.39 is generally referred to by the small filler desgnation "75mm A.P.C.B.C. (small filler or small capacity)" once the difference between it and the older type of ammunition became known. The 75mm A.P.C.H.E. refers to a large filler or capcity. No distinction in projectile designations may refer to either the 75mm K.Gr.rot Pz. directly, or alternatively to a period when the difference between 75mm K.Gr.rot Pz. and 75mm Pzgr.39 was yet unknown.
Further, the only actual test data, I see here, were conducted with 6pdr and 2pdr. Other ordnance items are estimates.
Not sure this agrees with your terminology....
British Ordnance Board penetration graphs from 1943 and 1944.
O.B./43/CV.12 May 25,1943
shows for 2400 f/s muzzle velocity (731.52 m/s) of 14.81 lb. APCBC shell ("MV as tested by trial in KwK 40") at 0 and 30 degrees deflection:
2400 f/s penetration 121/102 mm,
2000 f/s (609.6 m/s) 98/83 mm,
1600 f/s (487.68 m/s) 75/63 mm.
O.B./43/CV.13 same date.
MV 1350 f/s (411.48 m/s) same shell model:
1300 f/s (396.24 m/s) 58/48.5 mm,
1000 f/s (304.6 m/s) 41.8/34.8 mm.
O.B./43/CV.20 for 15 lb. large HE cavity APCBC
1300 f/s MV December 14,1943:
1300 f/s 50.3/46.25 mm,
1000 f/s 35/32.94 mm.
O.B./44/CV.50 for 15 lb. small HE cavity APCBC December 13,1944 of Kwk 42
MV 3068 f/s (935.13 m/s),
Pak 40 MV 2600 f/s (792.48 m/s),
KwK 40 MV 2300 f/s (701.04 m/s):
3000 f/s (914.4 m/s) 182/156 mm,
2400 f/s (731.52 m/s) 133/104.5 mm,
2000 f/s (609.6 m/s) 104/77.5 mm,
1600 f/s (487.68 m/s) 75.5/55.5 mm.
(I suspect the clover leaf diagram is based on the O.B./43/CV.12 May 25,1943
shows for 2400 f/s muzzle velocity (731.52 m/s) )