....then why don't you consider teaching adults at Yuming if this is really such a "great" place?

That's easy to answer. Most of the work at training centers involves teaching kids. In contrast, teaching adults at training centers is rather limited. Maybe it's okay for someone who doesn't mind teaching only 8 lessons a week. It's not suitable for me, as I require a higher income. But maybe you should try it, as you have previously said you have additional income not connected to teaching. You never know, you might fall in love with Tianjin - it's the third largest of China's cities in terms of its population! And don't forget how friendly and helpful the Chinese staff at Yuming are. The only problem I can see is the occasional backstabbing foreign colleague.