I disagree, here are the two scenes
first,
second.
The first I read as the librarian merely shrugging off the issue as Obi-Wan having the wrong coordinates.
The second Obi-Wan has already done all the work, and the answer he gets is 'just go and look' - but this scene allows him to highlight a potentially very serious issue to the grand master of the order, it isn't that he needs to be told it was deleted it is that it being deleted is such a shocking thing that Yoda needs to be aware of it - if Yoda hadn't been teaching a class at the time then the same conclusions would have been reached.