its simple if you read it,
WeaponDCAddValueMaxLimit=12
WeaponDCAddValueRate=15
Blue is the maximum amount of stats added. So if you Set value to 5, Max stats added would be +5.
Green is the rate of the drop. So if you have X100, If you placed at 0, then all items dropping would be normal.
So you want to stop iteems having to much stats added, you would edit the blue bit so the stats added wern't so high (possibly making 4 the max). Then If items still droping with added stats, edit the Green one, untill your happy
(i think thts ow it works :P, if not whoops)