Descent 2nd Edition rulebook, Page 8, Additional Movement wrote:
A hero may suffer fatigue to receive additional movement points during his turn. For each fatigue suffered, the hero receives one movement point. If the hero already has fatigue equal to his Stamina, he may not suffer any more fatigue to receive additional movement points (see “Fatigue and Stamina” on page 13). A hero player is not required to perform a move action in order to suffer fatigue to move. During his turn, before or after resolving an action or during a move action, a hero may suffer fatigue to gain movement points.
The short answer is yes, you understand correctly. In fact, one of the advantages that the heroes have over the overlord is the ability to perform two attack actions per activation, making fatigue-move, attack, attack a common activation.