Interesting ... we instead had a builder do all of this for us (ie. rather than going to an architect), and even though the end-result wasn't properly finalised (it was still a mess around the main bedroom ensuite & the guest bedroom) it came in about $300k over the budget we'd given them.
So if I were to be facetious I could say that, by putting out experiences together, the architect approach turns-out $200k cheaper ...