The frequency I see minor add4 chords in leadsheets and such is basically zero compared to the other 4 chords that are dom9 chords omitting 1 of the 5 notes.
if you put the bass on G, which i think is where it's supposed to be according to your study, i think you will find it much more commonly. or actually perhaps the lead sheet will just say G9 or Gmin9 but in reality the execution will leave out the 3rd