The ability for PMCs to "time" seems to bring about polarised opinions. A few magazine reviewers mention that this is one area they do reasonably well at. The only dissenting one I've seen myself was Alvin Gold in HFN. Then again, he's partial to Krell/JM Labs.
I never had a problem with it at the dealers, for all of the consumer range of PMC products (db1 -> ob1) although some people mention that the newer ones (gb1, ob1 and PLUS series) do bass better due to newer foam lining in the TL cavity.
When I heard my FB1s, I thought they timed well at the dealers. I brought it home and it was an absolute shocker regardless of positioning. Then after about 90 days, they seemed to settle down and are now doing quite well.
Maybe put it down to preferences as well as burn-in?