That was one main result, yes. It looks like Armstrong and Sotala counted the Michie survey as one 'prediction' (see their dataset here). They have only a small number of other early predictions, so it is easy for that to make a big difference.

The image I linked is the dataset they used, with some modifications made by Paul Christiano and I (explained at more length here along with the new dataset for download). e.g. we took out duplications, and some things which seemed to have been sampled in a biased fashion (such that only early predictions would be recorded). We took out the Michie set altogether - our graph is now of public statements, not survey data.