cost of goods sold

Can someone actually try and tell me if it is possible to write a negative number for line 36 of schedule C and it is ok? The other tax software I was using doesn't allow it. They say IRS doesn't allow negative there. But it doesn't make sense to me. (because if you pull more items from inventory than you purchase that year, that will be negative, such as pulling from existing inventory too) If we are able to do it with Turbotax, I will do it with Turbotax.