In a recent siege last weekend, a Howitzer was loaded with 4gp or less which caused it's shell to go directly down and was used as a way to kill players on a banner by parking with a howitzer truck on top of the banner and using this method with a shrappnel shot, they killed several players.

I suggest, to replace the gunpowder for howitzers with "Charges" which would load the howitzer in increments of 5 instead of 1

This will make it completely impossible for anyone to input 4gp or less to recreate the method used last weekend.