The way they do it in accounting, is gross sales
then you list expenses
and the bottom line is net income, gross sales (and other income) less total expenses
The P&L does this for you automatically
the fees, though something you have to pay, are not part of the sale. suppose you sold the item for cash across the table; no fees involved. And then you wanted to report on two sales of that item.
In standard accounting both items would show the same sales amount, which is correct.
If you tied fees to the sale, that would confuse the reporting of sale prices, some would be less due to the fees. That makes trying to determine whether to have a sale or whether to raise prices based on sales kind of hard.
fees are an optional expense, you could sell something and have no fees, or your fees could vary depending on how the payment was made (if you used more than one payment processor)
Taxes are an additional burden a business incurs. Taxes are not part of your income, you just collect them and hold them. Then you pay the taxes at some point. No income, no expense for the business.
