Spider-Man: Homecoming did $427,804 this Thursday, grossing so far $316.1m. It already added $2m to its domestic gross this week, and while the weekend will face adversities like the Mayweather fight and a tornado in Texas, I'm firmly confident that it's grossing at the very least yet another $2.8-3.1m this weekend.
I don't think getting to $330m will be that hard, it'll have a nice bump from the holidays next weekend. I think that by two Mondays from now it'll have crossed $325m already. Given the reception of the film and lack of competition, I'd say it still has a chance of grossing north to $335m. So let's see.
Well, going by your range for this weekend means you think there's a good chance it's going below Ant-Man's weekend number from a week earlier in its release($3.07M). It has been above that for the last 4 weekends, and over the last few weekends it has slowly gotten closer.
Ant-Man had very good legs, and it looks like Homecoming might fall behind Ant-Man's numbers soon. If it doesn't fall behind and just does exactly what Ant-Man did after this Thursday, it gets $330.2M (in this comparison they're in the same week, so both have Labor Day next weekend to get the same boost btw)
That's why $330M doesn't seem like it's guaranteed(since it pretty much has to keep up with Ant-Man to get there). And adding another $5M on top of that is very hard at this point (it would require over 36% more from now on than $330M does, which is a big difference).
I also think it'll be very close to $325M on Labor Day, but just below it by less than a million.
But that doesn't mean it can add another $10M from there. Getting to about $325M on Labor Day would mean it did roughly the same as Ant-Man adjusted over the next 11 days.
Ant-Man adjusted added just under $6.5M after Labor Day was over. Asking for Homecoming to get to $335M is asking for it to make about 1.6 times as much as Ant-Man adjusted did after Labor Day.
That's a huge difference for movies that are within 6% of eachother for 5 weeks in a row, right?
Homecoming's lead over Ant-Man has gotten smaller over the last few weeks, not bigger. To suddenly go from 6% (and dropping every week) to a 60% lead would be quite an accomplishment in my opinion.
I think it would need to do something different to Ant-Man, like an expansion or re-release, or keeping an unusual amount of theaters for a longer time through October (Ant-Man kept going all the way into mid December btw).
Anyways, that's another way of explaining why $335M seems very unlikely to me, even knowing that it's getting a boost from Labor Day which could get it within $10M from there within 2 weeks.
Damn, this really turned into quite the story didn't it? It seemed so short in my head xD