They are both slow ballads, like "Singin' the Blues." Oliver's "Olga" hit me as definitely more of the swing era arrangement than Moten's, which is definitely "jazzy" in style with a prominent rhythm section. Bix 's & Tram"s was closer to Moten's, in the traditional jazz mode, but had a different feel, since it's basically an intro, two extended solos, and a closing, with very little ensemble playing, aside from background chords, and Lang's near "duet" accompaniment to Bix's solo.