July-Feb, or August-Feb bellies were old crop v new crop. Somewhat, but really not similar to July/Nov or July/March beans.

Difference in spot v new ... especially bellies ... frozen stocks of July or August could not be recertified ... not a long term storable commodity such as oilseeds or grains ... ergo, rational differences twixt the two. Legitimate differences.

Please excuse and old Merc Jerk. But there were fundamental differences for the "black magic" spread differentials.