Cost and effectiveness in combat

I request a change in the cost of some units. The first one would be the towed artillery. The cost of 1000 supplies and 900 parts doesn't seem logical; it's too expensive. The maximum range is only 75 This makes it useless compared to rocket launchers, and the cost is not logical in the real world. Towed artillery is used because of its low cost and cheap maintenance. The cost should be changed to 1000 supplies only.

2 mobile anti-aircraft this unit is almost useless if it is not upgraded to level four, due to the patrol feature which allows aircraft to attack without entering its range (only range 26). This is not a problem with SAM batteries because of their greater range. There is no reason to cost this one, even though it hardly offers any advantages (only against helicopters, but it is hardly useful; it is better to build air superiority fighters). Its cost must be halved in order to be cost-effective.