[CONNECT C++] DRange3D initialisation

I found the DRange3D  struct in MicroStationAPI help.  It's grown from a simple data container in V8i to a useful class in CONNECT.

In previous versions of the API, we had to do something like this to initialise a DVector3D to max/min values of points...

void findHighLow
(
DPoint3d	*low,
DPoint3d	*high,
DVector3d       *range
)
    {
    //handle the low end
    if  (range->org.x <low->x)
	low->x = range->org.x;
    if  (range->org.y < low->y)
	low->y = range->org.y;
    if  (range->org.z <low->z)
	low->z = range->org.z;
    //handle the high end
    if  (range->end.x > high->x)
    	high->x = range->end.x;
    if  (range->end.y > high->y)
    	high->y = range->end.y;
    if  (range->end.z > high->z)
    	high->z = range->end.z;

    return ;
    }

Does this have the same effect in CONNECT?

void findHighLow
(
DRange3d&           range
DPoint3d const&	low,
DPoint3d const&	high,
)
{
  range = DRange3d::NullRange ();
  range.Extend (low);
  range.Extend (high);
}

If I've misinterpreted that Extend method, could someone explain what it does?