Yes, you got it. What I find easiest when working with the report layouts in the manner is this method:
1. Create and save the one modified report you want.
2. Export this report to a .package file (Tools > Customize > Customization Maintenance)
3. Open the .package file created in step 2 in Notepad.
4. There will be 2 places at the very top of the report with the report name - change both to the name of the report you want to save this as. The name has to be exactly how it appears in Report Writer in GP. (You might actually need to go into Report Writer and look this up.)
5. Save the file and import it into GP (same window as in step 2). It should import with the new report name.
This way you do not have to spend a lot of time modifying the layouts if what you need is similar to what you already have.