(a) Duty of Counsel. The prosecutor and the juvenile's attorney must advise the court of the impending expiration of time limits in the juvenile's case. The court may consider defense counsel's failure to do so in determining whether to dismiss a petition with prejudice.

(b) Motion to Dismiss. On the juvenile's motion or on its own, the court may set a hearing to determine whether the time limits in these rules have been violated. If the court finds that time limits were violated, it must dismiss the petition without prejudice, unless it finds that the interests of justice require dismissal with prejudice.