Yes it does seem as if they are closely related but he did mention that his motive was an update of Steockler (which is D23 for 35mm?). In Edge of Darkess, Thornton said that he lowered the sodium sulfite to increase sharpness slightly in response to modern finer grain films. Then because modern thinner film soak up less developer he changed from borax to more active and alkaline bath B with Sodium Metaborate.

I'm only starting to learn some of this, so be gentle if I read wrongly...
Best regards,
James