Hi @Arun KR
The problem is not that the state does not change to changeover since it does, but the FluidProcessor updates the state back to empty automatically after the Fluidprocessor has entered the changeover state. You can see this is you step forward after stopping at a breakpoint in the onMessage trigger. This probably has to do with the internal workings of the FlexSim engine so I guess only someone from FlexSim can answer that.
If you want the stats to be correct then maybe you can mark the start of the change over state into a label and when the state should end you write the value into the stats node directly. In this case you would need to reduce the empty state with the same value as well.
Another option is to create custom state nodes that you only update yourself. But this obviously requires more work.
Axel