Another quite powerful feature in MEP15 Plus is to use the audio mixer to adjust audio track levels not only at the beginning or the end but at any point between.
To do this open the mixer and preview your footage and adjust the sliders as the movie plays ... when you have finished you will see a green graph line on the audio tracks adjusted representing the volume level. This graph can be adjusted afterwards if you got the level wrong during the live mix by pulling on the green marker squares. If you don't like your mix it can be reset and you can try again .... give it a try