The banding would appear to be created along the direction in which the pano was shot - if you shoot in rows, the banding is stronger in the horizontal. If you shoot in columns, its stronger in the vertical.
Even in that Dubai 45GP one in the above link, despite the fact that the lense vignettes strongly, there is little to no banding horizontally. It's all in the vertical (that one was shot in columns).
These days I shoot pretty much exclusively in rows (360's) using the VR Drive 2.