That scene where he is looking at millions of possible outcomes and only one is a good one? Instead of possible futures, now he was looking at all the alternate timelines and looking for one to emulate, so that his timeline would have the good outcome. Does he just know that is what he is doing or does he still think he was just looking at possible futures?
So, we need to make some guesses...
We have the idea that the universe branches into a multiverse. We do
NOT have the idea established in canon that this is actual Quantum Mechanical Many-Worlds, in which
every possible universe is represented. And cinematically this makes sense. Otherwise the bulk of all the variant universes you'd never notice a difference locally. We get to see only a small local area around Earth. But, most of the universe is nowhere near Earth. So, most of "all possible" changes are far from Earth, and we wouldn't observe them. Statistically, if you crossed over at any time, it'd be to a universe that looked
EXACTLY like the one you left. Which makes for crummy stories.
This gives us the possibility that not all choices to guide yourself into the future are choices that create variant timelines. Some choices create a variant, and some do not.
Thus, there's no real way to know if Doctor Strange was looking at possibilities that are "within tolerance" for one timeline, possibilities for variant timelines, or a mixture of both. We might simply rest in the idea that, from Strange's perspective, it was not evident that there's a difference in the two cases. He saw results, not the multiversal cosmological implications of those results.