Bangkok - Shanghai - (Shenzhen) - Zurich

My partner and I are flying from Bangkok to Shanghai. We stay in Shanghai from the 26-30.3. However, our return flight to Zurich is with a change (with the same airline Hainan) for 6 hours at Shenzhen Airport. Is it a problem if we change in Shenzhen and would we still get the 144 hour twov?