Hotstart Running

[José María Santos Gamero]

Hello everybody, I am new in this forum and in first place I want to thank all people that make this possible.

About my question, I am working with EPA SWMM and I need to use a hotstart file for fist time. I know that I can generate a hotstart file (that contents the last instant results of a simulation) automatically from the interface files section and that I can save the hotstart file manually (for a specific time) from the GUI. The problem comes when I use the hotstart file. I do not understand how the hotstart file works exactly because:

• If I make a simulation to create automatically a hotstart file and I compare the storage value shown in the status report under “Flow Routing Continuity” section in “Final Stored Volume” with the final storage value in the table of the system storage results, I can see that both values are the same, which is ok.
• Then if I use the hostart file created in a new simulation and I see its status report I can observe that “Initial Stored Volume” does not exactly coincide with “Final Stored Volume” in the previous simulation (the simulation used to create the hotstart file). Although these values are not the same they are really close and I think that variation can be due to the use of different units and its corresponding approximations, but I am not sure about this. Why are these values different?   
• In addition, if after the second simulation I compare the storage value shown in its status report under the “Flow Routing Continuity” section in “Initial Stored Volume” with the initial storage value in the table of the system storage results they are not the same value there are a big difference between these values and I think that they would be the same. Am I wrong? Can anybody help me to understand why these values are different?

Thank you for your time and help

I await your responses

Regards