I cant answer your question without you answering mine first. You said it comes out less hard, I said based on what test, you replied w/ "feel". That is not a quantifiable answer, that is, literally, a feeling. I have test data that says SBA does not satisfactorily soften brass, you have nothing to counter that other than a feeling.
And i wouldnt say the collective knowledge on SBA is fabricated, but i would say its limited at best, and these test results prove out just how potentially ineffective it is when compared to flame and induction annealing.
And if you are questioning the potential bias in this test, why would they offer a budget alternative to induction being flame? they have as much vested interest in flame annealing as they do SBA...