fwiw, one of the FFT challenges is about the Scott encoding [1], while the other uses Church trees at least [2]. Both use a balanced ternary numeral system, which is a lot more efficient than plain Church/Scott and fairly well-known [3]. Either way, I would have assumed there to be a chance that at least one of the AIs had a look at [4] -- a tutorial about FFT in LC by the benchmark creator himself.