You can download the report and read it rather than filter it through a reporter.
Note, that is technically recoverable undiscovered reserves, and is only a small fraction of the oil in place in the formation.
According to the article at the USGS Newsroom the assessment shows a 25 fold increase over the amount of technically recoverable oil estimated in the 1995 estimate of 151 million barrels of oil.
That is a significant increase.
Development began in the Elm Coulee Field (Eastern Montana) in 2000, and now over half the oil produced from the Bakken has come from that field.
When the estimates of how much of the oil present in the formation is technically recoverable range from 3% of the oil present to 10%, with some estimates as high as 18% over in the Elm Coulee Field in Montana, you can multiply the recoverable oil by a factor ranging from 6 to 33, and get an estimate of oil in place.
Which is the 'other number' which seems to be causing this writer to get their knickers in a knot.
Estimates vary, but a better discussion of the process and the questions raised is to be found at the NDGS website which explains the development of the controversy in relatively simple terms.
Thanks.