Di Pasquale was studying sax performance at Northwestern under the great Dr. Fred Hemke when he wrote the Sonata as a composition assignment. (sidebar: there are legit Coltrane phrases in the 1st and 3rd movements.) Anyway, allegedly the final measures of the 2nd movement (that low Eb - D - Bb phrase) were first marked "subtone" in addition to "ppp". When Di Pasquale played the piece for Dr. Hemke, Hemke allegedly scoffed at the "subtone" of those final measures and insisted those notes be "full tone" at the "ppp" dynamic marking. Di Pasquale protested, insisting it was impossible to "full tone" those notes at the "ppp" dynamic. Hemke, in typical Hemke fashion, took out his own tenor and proceeded to demonstrate the final measures "full tone" at the "ppp" dynamic. Of course, those final measures are not marked "subtone" and, as someone who has played that piece in competitions, I can attest that you will be called-out if you do indeed "subtone" those final measures (accidentally or purposefully).