Andersen played a valuable role in the GF, but that wasn't enough to convince me that he should gp around again.
During the regular season, there were maybe 3 games where he had a serious impact. One was the 99-91 win over Adelaide at Hisense, where he was absolutely huge at both ends, and kept United in the game. Off the top of my head, I can't remember which other games, but I do recall there were a couple.
The problem is, in the remaining 25 or so regular season games (or 20 given he missed a few with injury), he looked a step or two off the pace. He's struggled with NBL reffing even in 2016-17 and then his game declined markedly in 2017-18.
Unless he carried an injury through 2017-18 that we don't know about, I'd recommend he retire on a magnificent high, as someone who just won his 12th championship and played an important role in that series.