The Code says that systems have to be installed per the Code and per the manufacturer’s installation instructions. In the event one is stricter than the other, the stricter shall apply. Common in this area is Carrier and Lennox both of which have very specific installation instructions including condensate disposal.
Several years ago a previous client called me to tell me this story…
“We came home from a 2 week vacation and opened the front door and half our house was flooded. There was mold growing everywhere. They had to tear out half the flooring and 2 feet of drywall in half of the house. They had to replace the kitchen cabinets and 2 of the bath cabinets. We had to live in a hotel for over a month while they fixed it. Because of your report the builder had to pay for it all, probably $50K or more”.
A few years before this we had performed his new build inspection. This same type of setup (except this AHU was installed on the slab in a closet) was the what caused the flooding, the cut-off switches failed and the AUX pan had no drain line installed (to a suitable drain or a conspicuous place).
The SOP is the bare minimum, you are free to use Codes and installation instructions as references to backup your observations even though that is well beyond the SOP. He was a younger guy with a couple of young children when we did the inspection.
The builders around here are taking every shortcut they can think of to save a couple bucks. Before all the price hikes what would it cost to run a few feet of drain line to the soffit? $10 and 10 or 15 minutes? 
