Installed lesser quality of heat and aircondition units also lesser quality duct work in attic space. Duct board is not an acceptable construction practice although is not completely out lawed it is on the very low end of quality.
Anyone thats has be in the construction industry knows in late eighties when duct board hit the market it was the new wave until early nineties when it started to break down and consumers were breathing fiberglass particles. It was phased out. You show in your models all metal duct work coated insulated inside that is the accepted practice by reputable contractors. Also you showed all high end heat and air units which was impressive.
To see low end units and duct board is very disappointing. I belive this is deception in a high end housing builder.
This is what someone would expect to get from low end house builder.
Review about: Dr Horton House Construction.
Monetary Loss: $2000.