That wasn't the apple and oranges content, but you're probably right on the other - as to how MRTP status will be considered by the FDA. However.....:
“Modified risk tobacco product” means any tobacco product that is sold or distributed for use to reduce harm or the risk of tobacco-related disease associated with commercially marketed tobacco products. Section 911(b)(1) of the FD&C Act. Sold or distributed for use to reduce harm or the risk of tobacco-related disease associated with commercially marketed tobacco products means a tobacco product ...
1. ...that represents in its label, labeling, or advertising, either implicitly or explicitly, that: i. the tobacco product
presents a lower risk of tobacco-related disease or is less harmful than one or more other commercially marketed tobacco products;
... since B.O. isn't a tobacco-related disease, any mention of diacetyl-free shouldn't apply.
http://www.fda.gov/downloads/TobaccoProducts/GuidanceComplianceRegulatoryInformation/UCM297751.pdf pg 6