Basically there is no tipping culture in China or should I say Asia, you pay what the fare is listed and that is. The service charge is included, and that is their job to serve you. Paying tips to someone would not give the incentive to serve better, it is more likely the guy respecting his job or not. At least for a Chinese, it is the responsibility to perform your duty and do not expect a tip. (The only place you have to tip is when you go for a massage)
But then we normally just round up the yuen for the sake of not getting those coins back, like 15.6 to 16 or 18 to 20
In Japan, it is an offence to give the tip.