I went back in my files and found the original photo before it was cropped and then zoomed in really close. I think for sure it's
not the parking garage for that white complex. It's the one for the reddish complex. Look just to the left of that reddish complex. There appears to be an attached white structure that's lower than the actual offices. The far left corner of that garage is "touching" the Moonlight Tower of the Zilker tree in the photo. I think that's the parking garage the photo you were asking about was taken from because the top floor looks like it's just barely above the tree line, and in the nighttime photo you were asking about, you can see trees in the foreground and the tops of streetlights.
Hmm... I need to find someone with a car who wants to go on an "adventure" with me.