For businesses, the laws and regulations often require the Income Statements to have a specific multiple-step structure. Also general recommendations usually include multiple steps, such as the following (I added the last step for the sake of consistency with more advanced instructions):

+ net sales
− cost of goods sold
= Gross Profit
− operating expenses
= Operating Profit
± extraordinary gain or loss
− interest expenses
= Taxable Profit
− taxes
= Net Profit
± appropriations and other adjustments
= Retained Earnings

In private households, we are not subject to any laws or regulations in bookkeeping. Nevertheless, we too could benefit from the general idea. For example, I wish to have the following general structure:

+ income
− taxes
= Earnings Margin
− expenses
= Wealth Margin
± changes in tied equity (such as home equity)
± changes in reserves (targeted savings plan)
= Savings Margin

The last step sums up transactions between expense and equity accounts. This allows me to represent the proportions of tied, reserved, and free equity completely independently from the way my assets are scattered around the various asset accounts - and independently from whether I use the GnuCash book closing tool or not.

Unfortunately, GnuCash Income Statement report simply clumps the end-of-period balances of all income and all expense accounts into one single profit or loss line. The easiest workaround I know of is to run the income statement for each step separately (leaving out less and less accounts in each step), and then manually merge the HTML files in such a way that the stepwise summary lines are included.

I understand that adding support for multiple steps might require big changes to GnuCash, but the need is very basic really. I am surprised to be the first one suggesting this.

More specifically, support for multiple steps would require adding a way for the user a) to specify the summary line title for each step, and b) to select the income and expense accounts to include in each step. An obvious additional (but not optional) wish is to support localized templates for the step specifications in the same manner as for the localized account trees.