Is it fair to say they are blending for strength/body Rob, rather than flavour? It's normally the ratio of volado to seco to ligero that gets talked about by the master blenders.
Don't get me wrong, I'm enamoured with the Cuban flavours, but it's not like one particular finca goes into brand A, and another into brand B. There is no "single estate terroir" as far as I know, it's all from over the Vuelta Abajo, and getting distinct (and consistently so) flavours, from the individual leaves that may end up in any particular brand, seems improbable.
It's more likely that the tobacco is largely the same for all brands, from all over the region, not selected farms per brand, and the blenders are aiming for strength & body profile (which they can control via ratios), rather than flavour profile (which they can't control).
Happy to be talked-down from here, but I think it's a pretty reasonable and robust assumption.