idk why it is even a consideration to make something act worse even for "balance", there is already enough bad unit behavior without making additional things work worse, they should only improve and be balanced around their proper behavior
also don't understand why or how you are supposed to make things be used differently based on rating, as if rating is some kind of physical parameter that can consistently or at all effect whether a unit functions or not
basically to make auto OC worse than manual OC you have to either make it act stupid (like mazor joked and I obviously disagree with such change) or have it physically a different and weaker weapon (makes no sense but at least the controls are intact, however now you have a weapon that only exists while you are manually using it (in an rts game)), and it already is better to manually OC if you can spare apm as you can pick better targets or wait a second for units to clump up instead of spamming it off-cooldown and hit less units with it, the only advantage auto OC has is it can shoot without stopping the ACU movement and other orders and ofc, without player babysitting the ACU and instead playing the game