Dear Orekit team,

I am trying to use the DSST propagator but I have some questions about the correct usage.

I would like to use the DSST propagator to compute a mean orbital state starting from a perturbed orbital state. For example, I would like to compute the mean eccentricity starting from the eccentricity of a perturbed orbit (which is not constant).

In the following lines of code I would expect that dsst1 and dsst2 produce the same results for a propagation:

```
State initialState;
DSSTPropagator dsst1 = new DSSTPropagator(new DormandPrince853Integrator(minStep, maxStep, vecAbsoluteTolerance, vecRelativeTolerance),true);
State mean = DSSTPropagator.computeMeanState(initialState, attitudeProvider, forceModels);
dsst1.setInitialState(mean, false);
DSSTPropagator dsst2 = new DSST(new DormandPrince853Integrator(minStep, maxStep, vecAbsoluteTolerance, vecRelativeTolerance),true);
dsst2.setInitialState(initialState, true);
```

What is the expected behavior for the two propagators?

Kind Regards,

Raffaele Ferraro