Do we know why Brian used a bass saxophone and baritone sax combination on Do It Again instead of (what had been) his previous standard of tenor and baritone saxes?
Those are two bass saxes playing a line in unison, not a horn section with any sort of harmony.
Also by the time Do It Again rolled around, the Two sax Tenor/Bari pairing was long since superseded by a more flexible approach, with many different sax and wind combos.