File size question ACX

First time audiobook user. My book is tooo long, 346 minutes. I am using version 3.2.1 on a mini Mac. I tried to see the track size (project is 17 clips) but only got the last clip size, 2.3 gb I think. I joined all clips, highlighted them all and tried again, but it repeated the last size 2.3. I shut down and opened it again hoping for a more accurate reading. What am I doing wrong. I need to edit before I upload so It will meet ACX standards. How do I get an accurate file length report?