Locking Product Schedule Amounts when an Opportunity is Closed Won

When an Opportunity is set to Closed Won, the Booked Amount on the Product Schedule is locked to preserve the values.

Viewing the Manage Schedules page, you will see that the values in the Booked Amount column are greyed out and uneditable. This preserves the values and means you can compare the revenue you expected when the deal was won with the subsequent revenue profile once the deal is implemented.

Remember, you can fine-tune the schedule profile while the opportunity is in the pipeline. After winning the deal, you can enter actuals and update your forecast.