Originally Posted by warbonnetguy
i've talked to them as well and was told the same thing about fill power. my understanding is that if the fill power given to the down at the time of processing is accurate, then steam conditioning is the single method that can bring it back to 100% loft, washing and drying or even just drying bring back most of it's loft, but not all of it like the steam condition. they also claim the best way for a user to bring back loft is to use the dryer set on low/med and add some tennis balls and a damp washcloth. they claim down is warmest with a slight moisture content.
if this is the case, it does make the most sense (imo) to list the highest achievable loft (kinda like using the widest point on a tarp as the listed width) as long as it's repeatable/testable with a steam condition fill test. it's known that down loses it's fill power with use, but nobody is going to run a fill power test on something like that, they would condition it first to restore the loft. if you took a heavily used 800 fil power bag and had it tested, they would remove the down, wahs and condition it and it should loft back up to the given rating, that was my understanding