Time to complete is an option for the addition of Task budget hours without affecting the original parent budget, it is generally applied to compensate for unexpected schedule events such as employee or machine unavailability.
Time to complete is opened by selecting Data on the very top menu bar or by opening Tasks on the main menu bar and right clicking a Task and selecting Time to Complete. The following form opens with a list of Tasks. Search and filter opens are available to narrow down to the specific Task:
Above we have 0.39 actual hours logged as labor and the inherited Task budget of 1.34 hours leaving a remainder or 0.95 hours (time to Complete).
We may decide that we need to increase the Tasks budget without affecting the original budget and insert an additional 2 hours, now the task budget (Inherited budget of 1.34 + 2 hours Task budget increase) has increased to 3.34, leaving a Time to complete the Task of 2.95 hours ( 3.34 - Actual labor(0.39) ) :
Remember to save these changes before exiting this form.
The above change can be verified in the Task view, where we can confirm the original budget (1.34), the change/delta (2) and the updated Task budget (3.34):