Information for custom timers is different depending on whether you view the TSD File or the Overview Report.
When viewing graphs in Performance Explorer we use the Source Type drop-down list to choose the way in which measurement information for the time period in question is displayed. This drop-down list can be displayed by right clicking on the results you are examining and selecting "Source Type". Performance Explorer will calculate and display:
- The sum of the values
- Their average
- A count
- The minimum or maximum value
- The standard deviation from the average
So for the graph Performance Explorer shows the average of all values while the Overview Report shows the real values of the complete loadtest. For example your graph is showing the Average of the minimum values, the Average of the maximum values etc, these values are taken, by default, every 10 seconds. If you are wanting to examine the exact values for a test you will need to use the Overview Report as this calculates values for the entire test.