We have this field set to Y for most template lines because we don't enter an Issue AU on the GL cats for IC locations. We also have some templates set up with multiple req locs as participants. So we want the AU to default from the RQ01 set up. We have some items like pharmaceuticals that are hard coded on the template line (and GL cat) to charge to Pharmacy so in these instances the field is set to N. I should also add that we maintain both stock and nonstock items in IC12.
If you set the field to N and you don't hard code the AU on the template line and the AU in the GL cat in IC12 at the From Location is blank and the Issue AU in RQ01 is also blank there will be no source to pull the AU from to the req line and the requester will have to enter this themselves.