Ability to use 144 hour visa free transit more than once

Is there a minimum time requirement to be out of China before using the 144 hour visa free transit option again? For example, for an itinerary of US > Shenzhen (Guangdong) > Hong Kong > Shanghai > US, is there a minimum amount of time we would have to stay in Hong Kong to be able to use the 144 hour transit option for both stays in China? Thank you