GCs keep telling me real wood can't pass commercial fire code. Not true, right?

I keep running into general contractors who swear real wood can't meet fire code on a commercial building, and that hasn't matched my experience. Some species pass the flame spread test with no treatment, and charred and fire treated products get there too. The real catch on bigger buildings is the assembly test, not just the cladding rating, so you need the documentation to back it up at the building department. I've been speccing from a specialty hardwood supplier partly because they can supply species that test well and actually provide the submittals. Anyone else fighting this with their AHJ?