What all are overlooking is the CHRISTIAN ORDER thing and the tax liability embarrassment of all those "unpaid volunteers". They are neatly explained IF you have a COMPLETELY SEPARATE LEGAL ENTITY where everyone is required to take the VOW OF POVERTY. The VOP is in the Federal codes, USC Title 26, I believe. The stipend is set out there, in black and white, with a statute number.
It is known as COMPARTMENTALIZATION.
What else is a loose end of the mystery is the back and forth of the ownership of the KH's: local >> WTS >> local again?
The fact that different countries have their laws and strange names for things is of little consequence to the comings and goings of the US TAXMAN. The WTS has never been one for such stringent insistence of standardized/unitized organization requirements from country to country as to cause this.
WTS has long realized that "when in Rome, do as the Romans do" works best when going from country to country. So these changes were to address US problems, not "feel good" worldwide unity issues.
Mustang