Just for clarification, I told him he could do either or. Building it all at once would actually save time. Because building it all at once would take 20 days.
Building each area separately would take this long:
Bleachers - 16 days
Lower tier - 9 days
Courtside - 7 days
Luxury Boxes- 6 days
Splitting it it 4ths would be 9 days. 9 x 4 = 36 days
I do understand what you are trying to say though, and there are situations to do both.