Originally Posted by: light487Yes.. why do people do that? I have seen C-flat used often as well.. is it because you are referring to it as sharp-5th rather than flat-6th.. and therefore makes more sense to say E#, since the sharp-5th of an A Major scale is E# (F) ?

It's mainly used to discern that note clearly and in close sequence writing music on stave.
The reason E# was used for the altered 5th note is because even though the "A"Major 5th was augmented, The Scale is still A Major........
and the A Major scale has the F# note in it.

There never should be any two notes carrying the same letter name in the same scale; Example;; A-A#-C-D-E-F-G
Bb describes the note position better and brings the B needed in sequence.

Another tid-bit. Scales with accidentals never mix then in the same scale.
If Sharp----all Sharp...... Flat----Flat.