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> There are costs associated with each sale, not everything is revenue.

"Costs associated with each sale" are irrelevant when considering revenue.

If you spend $400 to make a $500 sale, it's the same as if you spend $100 to make a $500 sale. Both are $500 in revenue. What's different is income, which is revenue minus costs.

I think the OP means that $400 is the retail price of a Surface, but the revenue listed in the report will be based on its wholesale price.

Costs associated with sale mean not everything is profit, but are irrelevant to revenue.

Revenue is income before cost of goods sold.