Why should your company spend all the money multiple the expenses of a local hire to send you to China? Here is my view.
There must be a gap between you and a local employee, and the gap must be substantial enough to justify the difference of the pay. Here some examples:
1) Trust. This could be the top reason to send you as an Expatriate. If your manager is unable or unwilling to trust a local employee for good or no reasons at all, you are positioned strongly in his mind.
2) Technical and business expertise. Through several years working experiences in Germany, you must have gathered practical know-how and skills, which you may not be aware of, but will sharp your judgment and decision making.
3) Leadership ability. Leaders are rare anyhow. Leaders who can run an operation with multi-national work force are like diamond. In my own 18 years working experience I had more than 12 bosses. I would consider only one and half as good leaders, less than 13%. Am I overly demanding? No. Conversation with others and literatures provided similar results.
4) Motivation to work hard. Since your cost is much more than your local colleagues, you might decide to compensate this with more working hours, staying late in the office and coming in on Saturday, traveling a lot and seeing less your family, if you can maintain one.
Do I miss any thing substantial? What is the added value in your special case? And what should be your strategy to stay in contract as long as you wish to?
A) Please find the ONE key reason for your Expatriate contract. Then do everything possible to improve that key reason. Example, if you are sent because your boss can only trust you, so do what is in your power to make him to trust you even more. If you are a born leader, than develop your team and your organization to a higher performance level.
B) Improve with moderate efforts in other areas. The strategy here is to keep par with your local coworker. You could do more, but your limited resource is the time, always.
C) There is only one thing you should be careful, which is if the key reason to send you is number 4). Then you should consider changing job, because how much more time can you work to compensate your cost? Twice than your local coworker the best case, but never, ever 5 to 10 times.