You can change the count frequency for an ingredient in the settings for that ingredient. Navigate to Settings -> App Settings -> Zip Inventory -> Ingredients. Select the ingredient you'd like to change, and in the middle of the page there are three boxes: Daily, Weekly, and Monthly. Clicking on any of these boxes will remove or add the Ingredient to counts of those types.
Quick note: Items in Weekly counts will also show up in Monthly counts, and items in Daily counts will show up in both Weekly counts and Monthly counts. This is to prevent missing any items when doing the Monthly and Weekly counts.
Hope that helps!