https://law.justia.com/cases/federal/appellate-courts/F3/238/1300/515379/p>

"The district court properly determined that Delta's pilots were engaged in an unlawful no-overtime campaign. However, the district court improperly interpreted the gravity and depth of ALPA's duty under the RLA to prevent such an unlawful job action. Because there has been no showing that ALPA lacks control over the pilots, reason dictates that ALPA has not done enough to fulfill its statutorily mandated duty to "maintain" the agreement and avoid an "interruption to commerce." Upon remand, the district court shall issue appropriate injunctive relief directing ALPA to take further steps to end the pilots' no-overtime campaign. Further steps may include issuing directives as drafted by the court and threatening (or imposing) union sanctions for violations, as permitted by ALPA's constitution.25  If ALPA complies with the court's orders and the no-overtime campaign continues, Delta may return to the district court for injunctive relief against individual pilots, as discussed supra Part III.C."

If the pre-Section 6 negotiation notice was that there was normally X amount of overtime being taken up by pilots, then to maintain STATUS QUO, the number X should not change.  Furthermore, the Union has a statutoryily mandated duty to maintain the pre-Section 6 notice norms or find itself being sanctioned by the court.   Particulary, if there is evidence of any concerted effort to pursuade pilots not to work overtime to "put a hurt" on the company, as we've seen here already.

You don't have to be a lawyer to understand this!   You just have to be an intellectually honest individual!