The first attachment to the site plan at about page 17 has a letter from Big Red Dog that says it's 12 stories of office and possibly three additional levels of parking as well as a five story parking garage. It certainly doesn't look that tall.
https://www.austintexas.gov/devrevie...erRSN=11223623
Edit: After looking at the rendering some more it does appear that it could be 12-stories and the three parking levels are connected to the office building (as opposed to being a podium) as seen behind the trees in the billboard rendering on the left.