To me it still looks bookable. Try some of the OTAs on momondo.it
I really like this fare, but there are too many factors which make it unviable. Firstly, my A3 qualifying year starts a week later on the 20th March. Positioning flights alone would push it up at least another 100 EUR and the 2 hour turnaround at AUS is also questionable. Being stuck in Texas might make this trip mighty expensive to get back to Europe!
That said, over 11,000 Aegean miles for the taking if you start at OSL (OSL-ARN-AUS//AUS-ARN) for around 150 EUR.
What are these flights about anyway? Why are they only on 2 dates?
EDIT: So this is why.....
http://www.austintexas.gov/news/scandinavian-airlines-sas-adds-stockholm-austin-sxsw-2018
https://www.sxsw.com/