Roundtrip cruise from Shanghai to Japan

We fly from Bangkok to Shanghai and stay for 2 nights prior to boarding Royal Caribbean 5 night cruise to Japan. We end up back in Shanghai and stay for another 2 nights before flying back to the UK via Bangkok. Do we qualify for the 144 hour free stay in both cases? I am a little concerned about re-entering on the visa free programme in a short period of time? And will the cruise line recognise the fact that we will be doing this?Many thanks for any advice.