Ah, yet another misapplication of the "Turing completeness" idea. Turing completeness is about results, not methods of computation. If two languages are said to be Turing complete, it means that they are able to compute exactly the same set of functions, and not that they do it in exactly the same way. For instance, you have a problem that in one language is solvable in O(n), but in the other it provably requires Omega(n lg n), because certain constructs (e.g., random-access arrays) are missing from it.