When playing Symmetra, her alt fire on her Photon Projector allows her to fire an orb. The longer you charge, the larger the orb is.  At max charge, a visual circle fills to a full circle in the center of the screen.  However, you can hold the charge even longer, so this is where I ask my question.

Do I have to fully charge the Projector, even past the regular circle for those extra seconds I can hold it to maximize damage? or is it once the circle is filled it is at max damage?