Hi Alan,
I never played the Piano 36 with a hose but always with the trumpet mouthpiece because you have better possibilities to modulate the sound; so I don’t know if it reacts differently with hose or without any mouthpiece. But what comes into my mind is that I often played without the water key, although it’s quite a mess with moisture coming out of the air hole while playing – to me it sounded a little warmer and softer. And perhaps this also leads to a more constant airflow through the octaves. I’ll try and report.