Ah yes, sorry, I'd forgotten about that. I have to take him at his word, but I don't have much faith that everyone involved shares Mr Seagers's logic or would stick to it in any sequel that happens. The Prometheus juggernaut was also de-biomechanised in production, and that had nowt to do with some plan to later recreate it more faithfully.
Still, it does follow; either an imperfect recreation by David, or his first original effort that he perfects in the finale.