Re: Odd timing
IIRC, the whole of Hubei province, about 60 million people, was shutdown by about Jan 27 or so. All public transport and factories were closed. I'd imagine that would have a quite significant and almost immediate effect.
It's be interesting to see a more month by month model, likewise for the EU and USA, over the last full year.
The bounceback effect will almost certainly show even higher than pre-pandemic levels IMHO, because factories will be trying to catch up on lost production and haulage companies will need to deliver all that stuff. Likewise, China, like or or not, is the worlds manufactory and has been coming out of lock-down a lot longer than much of the rest of the world because they had the ability to heavily lock-down and enforce it far more strictly than most other countries. They are making hay while the sun shine as one of the few countries operating almost normally at the moment.