I have seen outliers but yes I am going to call that a general rule for the tailored stuff. I tried on a DVN suit today in 50 (which is my Margiela size) at Barneys and it looked stupid small.
I have a DVN silk cotton jacket in 52 and it fits right although still on the small size of a 52.
Bombers I would say that large = 50, although they run short.
Totokaelo got a really good DVN shipment in -- velvet floral blazer and similar print pants, reversible floral bombers -- but some weasel bought out the fat people sizes at full price, so there was literally nothing there that I could try on without damaging it.
I am about thisclose to hording DVN things.