Don't use the word "under-expose" - it can lead to confusion in this context.
It actually means give too little exposure.
You want to be thinking instead about whether you should:
1) give the film the exposure recommended by your meter;
2) give the film more exposure than the exposure recommended by your meter - i.e. increase the exposure; or
3) give the film less exposure than the exposure recommended by your meter - i.e. decrease the exposure.
Whether or not you should follow the recommendation of the meter depends on the camera you are using and where you are pointing the camera at.
If you want to have good pictures of as much of a scene as possible, and in particular of the middle tones in a typical scene, point the camera there and do what the camera's meter tells you to do.
If you are most interested in the shadows in a scene, point the camera at the part of the scene that has lots of shadows in it and set the exposure for two stops less than what the camera's meter tells you to do.
If you are most interested in the bright highlights in a scene, point the camera at the part of the scene that has lots of those highlights and set the exposure for two - three stops more than what the camera's meter tells you to do.
The A-1 has a reasonably advanced metering system. More often than not what it recommends will be a good choice.
With negative film, if you are unsure, a little bit more than necessary exposure is probably better than too little.
But box speed and going with what the meter suggests will probably be good.