(a) Interpretation. These rules will be liberally interpreted to promote justice and facilitate the decision of cases on the merits. Cases and issues will not be determined on the basis of compliance or noncompliance with these rules except in compelling circumstances where justice demands, subject to the restrictions in rule 18.8(b).
(b) Words of Command. Unless the context of the rule indicates otherwise: "Should" is used when referring to an act a party or counsel for a party is under an obligation to perform. The court will ordinarily impose sanctions if the act is not done within the time or in the manner specified. The word "must" is used in place of "should" if extending the time within which the act must be done is subject to the severe test under rule 18.8(b) or to emphasize failure to perform the act in a timely way may result in more severe than usual sanctions. The word "will" or "may" is used when referring to an act of the appellate court. The word "shall" is used when referring to an act that is to be done by an entity other than the appellate court, a party, or counsel for a party.
(c) Waiver. The appellate court may waive or alter the provisions of any of these rules in order to serve the ends of justice, subject to the restrictions in rule 18.8(b) and (c).
Rule 18.8, Waiver of Rules and Extension and Reduction of Time, (b) Restriction on extension of time, (c) Restriction on changing decision; Rule 18.9, Violation of Rules.