For those who missed it, the "procedural error" was:
When a proposed rule will cause an impact of more than $100M, a preliminary regulatory analysis is required. The FTC determined that the impact would be under $100M, so did not do the preliminary regulatory analysis. The court decided that the impact was more than $100M, causing the "procedural error" after the fact.
Either it's a bad faith ruling, or, there's even more reason that the rule is necessary as that would mean that companies are leeching off more than $100M from customers through shady and anti-consumer tactics.