The change in workmanship is obvious at many, if not all, of the Inca ancient sites.
The base build is of high quality, massive stones, then built on top of that is low quality small stone.
Makes it fair obvious that the Inca came in as squatters on builds that were already long in existence.
It wouldn’t come as too much of a surprise to learn that the MP site was completed, or all but completed, by the previous regime, then taken over by the new guy, who managed to stave off the probably turbulent times that led to his rise.