When you press a key with your mouse you are getting a very very strong velocity. Thats cause you will likely click the key at the edge where it's louder than if you move in closer to the soundboard. Depending on your keyboard, the velocity response may be a little weak. To compensate for this try out some of the more aggressive preset velocity curves under the Control page. This is normall to want a little stronger attack.
Asus R500A-RS52, Windows 8, 2.6gHz i5 -3230M, 6GB RAM,
Cubase Artist 7.0.6, Wavelab Elements 7, Focusrite Scarlett 8i6, The Grand 3, Melodyne Essential, Superior Drummer, EZDrummer and Pop! EZX, Samson CO1, Yamaha P-35, Mackie MR5mk2 monitors, and more....My tunes on: Soundcloud