Thanks for getting back, Alberto.

I know you'd like to add a Job to the previous timesheets that were already processed. Yes, you can save the changes. However, it won't reflect on the payroll transactions and reports.

Additionally, the Copy Last Sheet button allows you to copy the data only from the recent timesheet. The best option for now is to manually enter or edit the details when you create a new one.

Intuit is always open for feedback. I can send a request to our developers, so they can consider adding more features to the timesheet. It will help them to make QuickBooks fit to every business needs.

Keep your posts coming if you need more assistance. I'd be glad to help you.