No offence taken.
The "common belief" I was referring to is that regulating the current would regulate the driving force, thus reducing distortion. This is not the case at LF (where distortion is prominent - at least in measurements, if not in audibility)because there are other non-linearities that are not eliminated by regulating the current: the variation of induction and suspension compliance when the voice-coil moves. These are particularly exacerbated at LF, simply because that's where the excursion is greatest.
I had not seen Hawksford's white paper; I can why current-drive reduces distortion at mid-frequencies, particularly in the mass-controlled region, where excursion is minimal, induction and compliance can be considered as constant and thus the predicament is verified.
As far as I can see, current-drive is not applicable to LF, in particular with tuned boxes, unless coupled with servo-control, or in a hybrid mode, voltage drive at LF and current drive at midrange, as you've done.