(a) If the defendants appear and show sufficient cause for their default on bail, to be determined by the court, the conditional judgment must be set aside; but, if the excuse is not sufficient or if they fail to appear, such judgment must be made absolute for the entire sum expressed in the undertaking, or any portion thereof, according to the circumstances.
(b) Excuses for default on bail must be heard by the court on application at any time when not engaged in other business. When a conditional judgment is set aside, no cost must be imposed on the defendants; provided, however, that this section has no application where money is deposited instead of bail.