I happened upon this by accident. Using both the SPG and the MLRS artillery, I have discovered that the minimum ranges are off in varying distances. The maximums are as well but are much less so, maybe 10 to 20 meters on those.
Attached image(s) show 1 meter less than the actual minimum distance according to the current game. {F22398} {F22399} {F22400} {F22401} {F22402} {F22403}