Ok. It is not obvious to me why you would see different results in these two cases. It is possible the two approaches have converged to different feasible flow solutions, but this is very rare in my experience. This kind of workflow can be used to test the feasibility of a given power flow solution,
If you find there are very large power imbalances this might be a bug in PowerModels, but I would need a detailed example to confirm and fix it, if that is the case.