Is the 72hr free transit also applicable when working for 2 days in China (Business Visit)?

Would like to come from Bangkok to Shanghai on Sunday late afternoon (Oct 8), continue immediately to Nantong (north of Shanghai, province Jiangsu) by train or taxi, stay there until Tu afternoon (Oct 10) and leave Shanghai by plane to Hongkong to continue travel outside of China. I'm German. .... or do I need a regular Business Visa?
Thanks