A lot of times, SSA users find that there is a slight difference in the results seen in the Time Series Plots and the numbers seen within the Analysis Summary in the elements Property dialog as shown below:
Figure 1.0 Different results seen in the Time Series Plot and Analysis Summary
The Time Steps section within the Analysis Options is the key to resolve this difference seen in the results. It establishes the time step length to be used for the runoff computations, routing computations, and results reporting. The Reporting and Routing Time Step is the most important thing for network analysis.
SSA uses a default Reporting time step of 5 minutes and Routing time step of 30 seconds. In most cases users tend to use the default and define only the Start and End Dates to perform the analysis. A very important thing to note here is that the Output Report or Analysis Summary within the element properties windows shows the results based on every routing time step whereas the Time Series Plot is generated on the Reporting time steps defined. This is where the difference emanates.