The Experience column from the Order Details report (known as the Audit report in Target Classic) was removed in the Target 126.96.36.199 (February 2017) release because it was determined that data in this column was mostly constant for any experience and didn't render much useful information.
I have reach out to Product API team for second part of your question & will get back to you ASAP.
Experience column have been re-added from March release for AB/XT/MVT activities.
For AP activities, we didn't add back experience column.
Also, The 'Experience' column from the CSV file generated via API won't be removed as of now.
Thanks & Regards
Thanks Parit! This is really very helpful.