Yes - Strict Theoreticians would call the last 2 notes "Bbb, B", but it is more user-friendly and common to spell them "A, B". Strict Theoreticians follow this rule : Any named interval (within an octave) involving any "C" to any "B", is, by definition, a "....Seventh", of some kind. Bbb and Bnatural are both measured and named "...Sevenths". One is a Diminished Seventh and one is a Major Seventh. The interval "C up to Cb" is not usually named a "Flat Octave", of a "Flatted 8th" - it just isn't done. I am NOT a Strict Theoretician. Thanks for your time, interest, and civility.