Hello there, userdwilliamsca. I understand you want to add a fourth column to your income statement.
The option to add one month in another column next to the current year-to-date and prior year-to-date is currently unavailable in QuickBooks Desktop.
Alternatively, you can export the report and open another Profit and Loss. Set the date period to This Month. Once done, consolidate the two outside QuickBooks.
Moreover, you can memorize the reports you've customized. This way, you won't have to do the customization process again.
I'll gladly assist you further in generating reports in QuickBooks Desktop. You can tap the reply button below to enter your queries. I'm always here to back you up.