Nikon doesn't recommend use of exposure compensation with matrix metering. I'm sure this information is given in the camera manuals. Altering the film speed to a lower value, however, will cause the meter to give more exposure throughout the film. This should solve the problem whether it is a problem with calibration, a peculiarity of this camera or the particular film you are using. Keep in mind the advice already given that many B&W films give better results with a lower than stated ASA value.