ArcGIS Server can provide some usage statistics graphs. It has ability to set report Age as predefined and custom intervals. Problem is that Server statistics time interval is calculated automatically and intervals differs thus providing misleading information.
For example Age value is specified to "Last 24 hours" shows max Total Requests = 2600
Custom Time Period for the same interval shows time graph for every 4h. Total requests > 10.000
It would be useful feature to specify custom time interval for Server statistics graph.