These two fields only appear on Sub-Recipes (not on raw ingredients). Cost per hour is your labour rate for making that sub-recipe; Time to prepare (Hours) is how long a batch takes. Sprwt multiplies the two and adds the result on top of the sub-recipe's ingredient cost wherever that sub-recipe is used inside a meal, so a labour-intensive sauce or stock correctly raises the meal's production price and profit margin even though no single ingredient line shows the labour cost by itself. Leave either field at 0 if you do not want labour folded into food cost.