From my understanding when i purchased it ....

The Pac-LC1 is nothing more than an external fade knob. It is not going to boost your volume. If your volume is on 25 on the head unit, that is as high as your Pac-LC1 is going to go.

Solution: I went ahead and bought two of them to sit side by side. One for in boat, one for tower. Now I can control each of them to my liking. (still have to use the volume on head unit to get to max volume). If you want to just buy one (due to cost), put the pac-lc1 to your amp running the in-boats, then just fade the in-boats down.