Accuracy values for the main guns - MBT's.

[JaM]

I found something strange. Im trying to find better accuracy ratings for guns, but during my tests i found that Firecontrol rating do only a minor bonus to accuracy.During my tests i tryed gun with acc 20, rangefinder 30 and firecontrol 0. i had accuracy at 2000m (target size 4) 64%. When i rised FC at 20,it rised accuracy to 70%, FC 40 made up to 76%. So only +6% at 2000m with 20 point Fire Control.Isnt it too low?