I think your estimates are a hair on the conservative side, but even so if you add these to the actuals through Tuesday it's over $281. I'm guessing its at $282 after Sunday, it's 5th weekend.
By comparison, here's what other movies have made after their 5th weekend.
Thor -- $12
TASM -- $12
BB --$26
Iron Man -- $42
IM3 -- $25
X:FC -- $8
Once movies get past their 5th weekend the percentage drop goes down. To date, this movie has outperformed all but IM3 on this list. I'd say another $18 is extremely likely.