Building and trees shading

Dear all, I'd like to discuss 2 issues: 1- Our project has most of the parking spots outside, at ground level. At the same level, there is an area for parking, under columns ("pilotis"), of total 5,102sf. Is it possible to consider this area under the bulding, but adjacent to the outside ground floor, as hardscape? This way we could consider this part of the hardscape shaded. 2- For the calculation of the shadow of the trees, we're using the 10, 12 and 15h shades. But as the trees are close to the boundary of the site, at 10a.m. the shade goes ouside the site. Nevertheless, should we still go for the arithmetic mean of this 3 times of the day? Thanks a lot!