My friend with the two (very very very) 2E sons (both PG and LD, but different diagnoses completely) told me she actually *prefers* 504 because it provides accommodations, while IEP doesn't. She, however, has a lot more personal resources at her disposal than I and can afford to pay for whatever services her children need.
Just so you know for yourself, this is incorrect. An IEP can and usually does include accommodations as well as specialized instruction.
"No academic consequences for behavioral issues" sounds like a perfectly appropriate accommodation to put in a 504 to me, although you might have better luck treating it like spelling for a dysgraphic kid - "No reducing grades for behavior unless the assignment/assessment is specifically intended to teach/assess behavior." And it may not change teacher behavior, but I don't see anything wrong with saying "DS does not respond well to raised voices" and "DS does not understand sarcasm," either.
