No on my computer at least. I need to open the sound settings dialog and move the slider to use a setting over 100%. So in this regard, there is no advantage to using the sound indicator as the existing volume control and sound settings can do the same thing. One other thing: the sound indicator applet does not show any indication the level is over 100, but the existing volume control shows the correct level in the tooltip (130%, for example). In addition, the existing mate volume control is adjustable with the mouse scrollwheel by just hovering over the panel icon, but when using the indicator applet this does not work in MATE (bug report #1421436).