My guess is: it generates a new metric file based on your customer defaults; the same as if you go to File -> New -> Model, metric units, blank template.
Irrespective of what base units an NX part file was created in, the Parasolid data is always saved as Metric. In fact, even with Metric parts the units are not the same. From the user's point of view, Metric files are using the base unit of 'Millimeters', while in fact, Parasolid is saving everything in units of 'Meters' (and before you ask, there's a very logical and mathematical reason for this convention).
John R. Baker, P.E.
Product 'Evangelist'
Product Engineering Software
Siemens PLM Software Inc.
Industry Sector
Cypress, CA Siemens PLM: UG/NX Museum:
To an Engineer, the glass is twice as big as it needs to be.