1.) Aside from physical goods there also intangible ones. However, these items that might no lonnger be necessary and can't be measured like customer loyalty, brand recognition, etc.
2.) Depending on the complexity of the business, they flow of goods and services might not be too easy and the accounting method may be different. Some numbers may fall into that category.
3.) Alongside intangible costs, there can also be far-wide estimates and dependencies on biased judgments like usefulness, salvage value, or depreciation.
