It is not a ten day auction
We do not ever change the original date the auction was posted on
You posted a picture of your durations not what the actual duration the auction is from the products table
Like i said i have tested the code easy to do i just manipulate the enddate on a test and run the cron
On a 5 day auction we correctly renew for another 5 days.
I am beginning to think you are expecting the code to also change the original date an ad is posted to the time when the cron is ran.