The problem is that a thrown hand grenade is detectable by the system, but well under the limit.

One publicized case of a soldier in a vehicle "protected" by this system but killed by a tossed hand grenade or hit by a grenade launcher from long range (ordinary 40mm grenades are only fired at about 75 m/s at the muzzle), and there will be calls for this value to be adjusted.

The system rightly should not react to tossed hand grenades or ordinary 40mm grenades, just as it shouldn't react to rifle rounds or thrown rocks - those grenades have no chance of penetrating the tank's armor anyway.

If soldiers are exposed, then such a system reacting is a greater threat to their lives than a hand grenade; triggering the system is quite likely to harm nearby troops.

The system is also capable of detecting firearm projectiles, but is specifically tuned not to react. Regardless of what calls may come, there won't be a change because the designers and the customers have already considered that possibility and specifically excluded it as not being worth the risk. This is not a case of being too cheap or short-sighted to do something.