Not sure. I wasn't on the survey, a colleague took the picture. We were only concerned about moving flues out of the way of some planned higher work. This was interesting but out of my scope.
From a water infiltration and duct sealing perspective, it's probably cheaper and better than cutting the duct assuming the existing roof penetration works well. It's just ugly as hell and not elegant at all. Also the electrical portion of the work looks wonky as well.