I got spoiled using 0W40 and 5W40 in everything and not having to
plug the cars and trucks in during cold weather.
Then I tried 10W40 last winter, but changed the oil before going
on a 3,000 mile trip in October.
By the time winter was half over at the 5,000 mile mark,
the cold starts were becoming an issue.
I thought that the aged oil should have been sheared down to
a 5W30 by that point, and cold performance better.
The Lubrizol demonstration shows otherwise and confirmed my observation.