The joke seems to be these exports come with a manual with a section that goes "you should not removed the dead weight highlighted here and replace it with additional propellant because then it will result in ranges exceeding 300km, and that would be very naughty ".Also China exported rockets always say range 280km, 290km but I think everybody knows the truth.
Several WM-80 MRLS sold to Armenia have been destroyed by Azerbaijani loitering munition:
Correct me if I'm wrong:
1 - 120mm SP mortar on ZBD-04 chassis
2 - ZSD-89 Armored Command Vehicle
3 and 4 - PLZ-07 122mm Self Propelled Gun