One of the things you learn as a long-time listener to the music The Real Group is a sense of musical malleability: the idea that their compositions and arrangements can evolve and change over time. An original version can be rewritten, expanded for a studio recording, and revised multiple times over the years. You can hear that clearly in multiple versions of “Chili Con Carne” but it’s really true for a wide swath of their material – in their two versions of “Since You’ve Been Gone” on Spotify or in comparing live and studio versions of “The Grass Grows Greener.” (That’s where I’ve been digging deep recently, as I study and rehearse this piece with GRCC Shades of Blue.)
We can worry about being accurate to the score, but it’s even better to be accurate to the core musical idea. The published score represents one way of executing the core musical idea. Dig down into what’s underneath the notation, and then figure out how to represent that best with your ensemble. Don’t hesitate to alter the notated music – so long as altering it doesn’t affect the core musical idea.