Or perhaps Mills never really understood quantum mechanics? Now, no disrespect intended.
What many people don't know: Newton mechanics of coupled rotating bodies is undergoing quantization too. Thus quanta are based on mechanics. The term QM has been wrongly chosen because its key feature is not quantization. Key is the association of a "mechanical" quantity with a probability for its "not so exact - HUR" location.
The drawback of such a concept is the complete loss of determinism. With QM you can calculate the absolute value of a photon's energy but not the angle of ejection or the vector for the recoil. Thus there is no surprise that Mills Newton like treatment, for the major part of the problems, leads to the same solutions as QM.
The "hidden" details are what really count. QM math adds unneeded freedom, that leads to some inaccurate distribution of quantizations. But worst: The QM overhead introduces the overall need for square integrability. This prevents QM from using the correct representation for internal magnetic fields.
Classical QM, as an engineering method, is OK for higher level orbits in the low sub - eV regions, but the computing overhead is gigantic.
To calculate the ionization energy of H2+or 4-He+, with Mills method, I just need a spread-sheet. and I get 2-3 digits better precision than QM with a super computer...
Final conclusion: What Mills added, is the correct treatment of the internal magnetic energy, that was missing in "classical physics QM" ..!