Looks like this was sorted in the answers but two flight numbers will always be two flights. A single flight number will be just one flight, if you go straight through, but if you stop the trip and then resume even with the same flight number, it’s two flights. This used to be a real sweet spot for tier points on flights that had a tag-on leg, such as GRU-EZE in the past, particularly back when they were awarding the same amount of tier points for each leg (they’ve reduced that now, but back when I was often on the 246/247 service from/to EZE with a stop in GRU, spending a day or two in São Paulo would often lower the price and double the tier points).

Now, what I don’t remember is if it was possible to take the same flight but booked as two segments instead of straight through as a single segment… I feel like I might have done that once when the old 247 was involved, but I’m unsure. To be clear, the ticketing would have shown both flights separately as opposed to just one segment. I’d be reaching back further than my current memory can in order to be sure, but I feel I may once have done that in my tier chasing days.