I think the conclusion is only partially correct — LightCarbon does actually publish parts of their testing protocol:
https://www.lightcarbon.com/testing-process_n23From that page we know their stiffness tests are based on lateral deflection under load (N/mm), with defined lever arms (~250 mm head tube, ~260 mm BB) and minimum thresholds (100 N/mm head / 120 N/mm BB).
So the values are grounded in real structural testing — not purely marketing.
However, direct comparison with Roadbike magazine (or other labs) is still problematic because stiffness numbers depend heavily on fixture design, load position, and measurement method. Even using the same unit, different protocols can produce very different absolute values.
Most likely the published LC figures (117 / 185) are normalized indices derived from internal N/mm measurements — useful for comparing LC frames internally, but not 1:1 vs other brands.