Believe the cooler/time period aspect is the relative time available which can rest above 140 degrees.
Having medium rare meats (below 140*) resting longer than 1 hour... sounds likely be a food-safety issue.
Cooking at Mason-Dixon BBQ Services
Lang 84 Deluxe Kitchen known as "The Glamazon" , Custom Klose Backyard Chef... of Snot, and a 22.5 WSM
Lang 60 Mobile - The Damsel II, Lang 48 Patio - The Damsel, Bubba Keg Grill - RIP, Double Barrel Smoker and a BSKD