No, that's not true. The following are now using the Start-72-hour-Clock-at-Midnight 00:01 rule: Beijing, Chongqing, Guangzhou, Hangzhou, Shanghai (Hongqiao and Pudong), Xi'an.

The following are still using straight 72-hours Scheduled Arrival-to-Scheduled Departure: Chengdu, Dalian, Guilin, Kunming, Shenyang.

This is already in TIMATIC systems, so somebody probably needs to update the Wikipost for this thread.

It's possible (probable) that in the future, all 72-hour TWOV transit points will go to the 00:01 +72 hours rule.

But this should answer TonyBurr's question above. At PEK, he arrives on Monday at 14:00 and his 72 hour countdown does not begin until midnight (technically, 00:01 on Tuesday). He needs to vamoose from PEK by the very end of Thursday (technically, 00:00 Friday).