Provider used the 'SetResourceUsage_API' PBA API method to update resource usage in a customer subscription based on the DUMMYGATE.
The request completed successfully, and still the resource usage shown in the PBA Provider Control Panel on the 'Resources' tab in the subscription properties is not updated to the value Provider specified in the API method.
The resource whose usage Provider set in the 'SetResourceUsage_API' API request is non-additive.
For additive resources PBA always shows the last amount set by the SetResourceUsage_API method as the 'Usage' value in the Provider Control Panel.
For non-additive resources PBA takes into account resource usage history and period of time each amount was used within the Billing Period and shows average usage of the resource for the proper period in the Control Panel.
Refer to the following article for details on non-additive resource usage calculation - How PBA calculates usage of non-additive resources.