I originally ran across this item on the Toyota forums.
The forum discussion was similar to one that I read on this site recently.
The 2019 Toyota corolla Hatchback requires the use of 0W16 oil.
The owners manual states that If SAE 0W-16 is not available, SAE OW-20 oil may be used
However, it must be replaced with SAE 0W-16 at the next oil change.
This was all fine and the discussion of 0W16 went back and forth with some noting that modern engines are engineered with tighter tolerances etc etc
and required the thinner oil.
About 10 months into the discussion, a person from Australia chimed in and posted the requirements for the same car in Australia.
In that manual for the same car and engine allows you to use 0W16, 0W20, 5W20, 5W30, 10W30, and 15W40.
I posted the page from each manual below. Both manuals list the engine part number as M20A-FKS.
The question is, why have we been fed this requirement with the threat of voiding warranty when in another country the same car and engine is fine with up to 15W40??
Is this the same with other cars as well?
The link to the the manual in Australia is here: http://toyotamanuals.com.au/docs/corolla-hatch-owners-manual-jun-18-current/