a major third is hardly ever done because the 11th is pretty much the same idea as per major triad as the 'sus 4', and the presence of both is a clutter, less flexible and kind of ugly. However a minor chord might be extended out to 11 for its sonority and is its own thing.MadBrain wrote:the 3rd should not be played on 11th chords
but not as D13 because "13" normally implies that you still have the 3rd, but not the 11th because it would be too dissonant against the third).
If I see 'D13', I assume a seventh but not more per se; I would indicate more if I totally required those notes. An 11th and a 13th on a dominant type seventh? the 11th is #11 in the idiom.