I just completed a '150 hour' TWOV (but inside the official 144 hour when starting from 00:01 the day after arrival).

Check-in at TPE for Air China (handled by China Airlines) was no problem, took a couple extra minutes but the check-in staff were aware of the 00:01 start. They double checked with a supervisor who had TIMATIC up on screen.

PVG - there are now clear signs for 24/144 hour TWOV - involves a long walk all the way to the right of the immigration hall. Single staffed counter (with options for more desks at peak times I guess).

Being 'over' 144 hours by raw counting (but within the rules at 00:01) this took more time - the officer had to call for assistance. They wanted all the info - ticket out, hotel accommodation, personal telephone number in China.I didn't have a new SIM card yet to which they were surprised, but I offered either the number of the hotel or a friend's number. They accepted the friend's number.

The onward ticket was photocopied, the hotel confirmation was sighted (paper print out). The friend's phone number was written on the top of the landing card (I had to do this in the area indicated by the officer).

Glad I was #1 in the queue - it had grown to 4 or 5 deep by the time we finished. Possibly would have been quicker being inside of 144 hours but I guess it took about 5-7 minutes all up (seemed a lot longer).

So sort of testing the limits in terms of time but no real dramas.

Outbound immigration no problems.