Thanks!

For example, a landscaping company buys soil for a project. They use the soil at a job, maybe they use all of the soil and maybe they have some left over to use at the next job. They charge the customer for the amount of soil that was used, plus labor and design work, in one invoice. 

Soil is bought very frequently, almost for every job (sometimes there is some left over but sometimes one job takes it all). 

Inventory is not being taken of the soil, so on the schedule C its price cannot be used as a COGS - the price should be used as an expense. 

So schedule C instructions would not have you categories this as a COGS, even though it can be debated that the soil is a "cost of the good that is sold", which is the combination of the service (labor and design) and the materials (soil). 

It seems weird to categorize something as a COGS in QB and then do something different on the schedule C..