I know you are correct and article should fixate on newly increased volumes instead, and believe the USGS is attempting to remain relevant.
When the Bakken was rolling along nicely, development wise, the USGS increased the reserve estimates because of the new data provided by new producing wells. They did that a couple of times and finally, the 'boom' was on--but those of us who had been in at the onset of the play had already been drilling wells like crazy for six years at that point. (First Elm Coulee in MT, then the wells by Stanley, ND, and elsewhere along the Nesson Anticline for starters). Drilling became more widespread, but the reserve estimates always seemed a little low.
There is a reason for this, simply that the USGS was avoiding hyping a play by making unrealistic reserve estimates. Even the State of ND was not excessively optimistic in their estimations, and a little caution is prudent in that regard.
Lease speculators and others will do the hyping; the government agencies which are doing serious oil and gas or geological science have to maintain their credibility in the long run.