Hitting the note.

It's clear enough on an ordinary tuner if I blow Ro accurately as D. If I use the downloaded shakuhachi tuner Ro appears as Ro over a fairly wide range before it appears in its flat form or shape shifts to tsu meri. I aim to practice it in its "purest" form but is the wide range on the tuner a reflection of the idea that Ro, or any of the notes on a shakuhachi, is acceptable as a "wide" note?