If they're willing to refund/replace the product and are standing by their specs than maybe you just got a dud. The first runs through any manufacturing plant always have hiccups.
And yes I've seen those reviews (and similar from other sites). Looks like people spouting marketing material in exchange for free gear. They nearly ALL say the same thing, or close enough that it'd flag a plagiarism checking service. I don't buy the immersion tests as valid because as shown on another thread, prolite gear is doing some testing and demonstrating that the water proofness of the DWR downs is marginal at best. Basically down has builtin lanolin that does the same job and the new downs are only better in very specific and not very real world situations. Plus immersion or rain tests actually tax the shell fabric far more than the down itself (and remember rain only happens around and above freezing, temps that should make you roast in such a filled jacket).
While I'm still not convinced it's a true 9oz down jacket since many people say the rab neutrino endurance (8oz) is warmer even though it's fully sewn through, albeit longer cut. Look at the Feathered Friends Helios with 8oz of down. Put on a person they look so much puffier than the mojave.
My guess is that it's 9oz in the largest size offered but in the mediums it probably drops down to the 6-7oz range. Assuming that there aren't two versions floating around Since it's 800fp this would put it on par with say a MB mirage (5.3oz 900fp) or the MHW Hooded Phantom (but with DWR down). Those are warm jackets for sure, just not deep yellowstone winter warm. I'd definitely get a replacement. At the very least they'll probably make sure you get the loftiest jacket in your size that they have in the warehouse and then you will have a nice fluffy DWR down jacket for yourself, regardless of what they sell to everyone else.

