Offtoa uses many of your stated assumptions to compute the COGS, so any of these could cause a row of your COGS on your income statement to be all zero:

1. No Raw Materials Used in the Product. You may have indicated that no raw materials are being used in this product. On the menu, select assumptions/costs/cost of goods sold.
2. Price of Raw Materials. The prices you pay for the raw materials used in this product could be zero. On the menu, select assumptions/costs/raw materials.
3. Not selling any of these products. If you don't sell any these products during this period, you will not have any COGS for these products.

Related Questions:

How does Offtoa calculate cost of goods sold?

Where do I enter/change raw materials?

How do I relate raw materials to products I sell?

Why do I have zero COGS?

Why do I have zero COGS for just one market?

How do I change the price of a raw material?

How do I change the number of units that I expect to sell?

How do I suppress a line of all zeros from a report?