Market value. What is a house with noxious odor worth? ...compared to a similar house without nasty smell? What would it cost (if it even COULD be remediated) to get rid of the stink? Note the noxious odor in the report (kinda like insect infestation problem which need remediation). Even with value adjustment, FHA may not go for it because it affects livability, house, occupants, and collateral value.
Years ago I owned an old duplex where the elderly owner lived upstairs with her dogs, was fearful of taking them out for potties, and the floors had soaked up decades of urine (curled up the edges of the wood flooring boards with gaps), and even the wallpaper and plaster walls were eeeewwwwww STINKY. I stripped, primed, sealed & repainted all the walls. Sanded the hardwood floors, put a dark English Oak stain on it and 4 coats of polyurethane, and that killed it. That said, cat pee is stinkier than dogs.
In another case, a friend of mine died and remained deceased in his Milwaukee flat for 23 days before being discovered after I sent the police there to do a wellness check on him. I arrived 5 days after the body was removed, and the smell was something I still can't get out of my memory. The building owner hired ServiceMaster for remediation of the odor, and there were still ventilation machines and chemicals on-site when I arrived. I understand eventually they resolved the odor.
If you have a ServiceMaster business in your area, I'd give them a call. Also, check with your city's death clean-up contractors; they may very well have chemicals to purge stink. Crime scene cleaners are known as bioremediation services, and I'll bet they have solutions.