Just intonation.

Doing ear training to a piano was once the only viable way...notice how SO many of the greats came from choral backgrounds? There's no reason the app can't dynamically tune the intervals correctly rather than playing notes of equal temperament instruments.

I wonder how many ...

He said harmonically...I have the same issue. I blame it on my decades of playing rock/pop/sould guitar, where the two are utterly interchangeable...meaning, a typical comp over and Amin chord would involve every variation of A/E...E/A...C/G....G/C....

The melodic is where the song examples help ...

Is this not a standard? I've never seen a theory book spell a typical jazz progression as IImi - V - I....it's always been ii - V - I.

Have I spent 20 odd years in obscure texts? I don't remember this issue in EM5...