From Kulala Lumpur to Beijing to HongKong to Chengdu.

Hey,
I'm from Germany and are planning to get the 72h transit visa when I enter Beijing on the 06.09.17 One day later at the 07.09.17 I'm leaving Beijing and fly to Hong Kong, where I'm visiting family for two days before I'm returning to Germany. But my flight home has a 12h layover in Chengdu. So, I would arrive on the 09.09.17 in Chengdu and leave it 12h later at the same day. Can I apply a second time for the 72h free transit in Chengdu (within one week), or do I need to spend the whole day at the airport?