This reply might very quite useless to the OP as I don't have any idea what the Chinese visa situation in Germany is, but my initial thought is "why not just get a multiple entry visa and not worry."

Again, not sure if that's an option in Germany (and the OP already has the visa, so likely even less of an option now), but in countries where a multi-entry Chinese visa is possible, there's no downside to getting one. For a US passport, the cost is the same and the visa is good for a year.