Friend of mine used to run an Ice Cream store.. he started as the "Delivery boy" pedaling his bosses product around the neighborhood by bicycle to the customers who called in an order (They made it on site by the way) and many many years later, after his kids had graduated college. He was still the delivery boy, Delivering by Pick Up to many customers and by Grayhound package express to many more.. Only difference is he was now also the boss. (owned the place)
Henry's Ice Cream, Battle Creek, MI.. Now history.
Well, he explained that there are some ice creams that the colder they get the harder they get.
And others.. You can chill them to zero, -10 or lower and they do not get harder.
So what kind flavor of ice cream do you have.. Some of them never get "Rock hard"... Once you have that figured out check with your local Ice Cream Parlor to find if that is a "Soft Flavor" or not.
if the freezer is hitting "Below zero" Vanilla should be hard as a brick.