Not the 'entire block'; the size of the parcel the building is on. The tower has 6X more floor area than the size of the lot it is on, and since it is 30 stories, it would take six 5-story buildings (each with the same floor plate size) to cover the whole lot - and it would still just warrant a ranking of 6. So what to you would be more dense - a lot 100% filled with six 5-story buildings or the same lot with a single 30 story building taking up 1/6 of the block's area (with 5/6 being grass)?