If a defense of untimeliness is not raised at least seven (7) days before the scheduled hearing on the merits of the grievance, the parties will be precluded from arguing that defense. However, where a party learns of facts supporting the defense fewer than seven days prior to the hearing, during the hearing, or in a post-hearing deposition, the party must present the defense to the opposing party and arbitrator within seven (7) days of when the facts supporting the defense became known or reasonably should have been known to the party. An assertion at the hearing, or subsequent to the hearing, of a newlydiscovered untimeliness defense will enable either party to present additional testimony, including the opportunity to recall witnesses or call new witnesses.