With OLC/ACM, weapon officer assistence will just give you the option of letting him ID ships for you. (which comes without a realism % penalty) He does nothing else.
You may have forgot to press apply when changing your realism settings. If you just press ok your changes will not stick. Or it could have just been down to typical SH3 weirdness. SH3 is a very unstable and buggy game, as you will find out the more you play
