Although NYC condenses ingredients in the shopping list to the larger units, the final unit is determined by the largest unit used in recipes and not by a store unit that you might prefer for a given item. In other words, if recipes in your meal plan include milk in teaspoons / cups / quarts, the shopping list will be condensed to quarts of milk. If the recipes include milk in teaspoons and cups, the shopping list will be condensed to cups of milk. But you would like to have it in gallons of milk for your trip to the store.
Here is a clever workaround suggested by one of our NYC power users:
1. In your meal plan, add a "conversion" recipe in your menu that lists 0 (for v5.48 and later) or .000000001 (for v5.47 and earlier) for the quantity with the unit that you want used for a particular item. For example, put “0 gal milk” as one ingredient in the “conversion” recipe to handle the milk unit issue above.
2. Save your menu to create the new shopping list. Exit the meal plan and open the shopping list.
The shopping list will then condense on gallons of milk. In the context of the above milk example, you might now see 0.59 gal of milk in your shopping list instead of 9.44 cups.