Hello Janice,
The capacity planner reflects the initial estimate to get the project done so even though an RM may approve less time from a resource, it doesn't necesarily mean that the project could be done any faster. It just means the RM doesn't have enough resources. We want the capacity planner to retain the Required estimates for better planning, not to cap off at whatever time is available.
If the approved time is sufficient then the PM needs to adjust the Required time in order to affect the capacity planner. Perhaps a setting or "leveling" option to reduce required time to approved time would be a good feature for scenarios like yours.
Steve Thompson | Solutions Consultant
Daptiv