The PBO assumed that the overnight rate would remain at 1.0% in its April report. In this one, it posits an increase of 25 basis points every quarter starting in January 2018, until the overnight rate hits 3.0% at the end of 2019. Given that the overnight rate has never been higher than 1.0% since 2009, it is hard to imagine that it will march up two percentage points above that in two years. This isn't mentioned at all by Tang, who perhaps looked no further than the executive summary.