Also update the firmware to 3.11, that allows the option in Reading Settings to show percentage left in a book or chapter. I use the book option as thats what I display on the kindle. Links to the firmware and instructions are in this thread
https://www.mobileread.com/forums/sho...d.php?t=185660
You want this one in the first post
Oct 2014 Release - 3.11.0 - The Skippy the Bush Kangaroo Release and its this update you need to install
Mark 5 Hardware : New Aura (and probably the Aura H2O)