Well, the response from the distributor is that about two years ago Laser Products added an "extra filament" to the P90 bulb, and that is responsible for the lack of a circular "hot spot" as good as the 6 volt lamp assemblies.
They say that the degradation of the beam shouldn't be "extreme", however. I would consider the "oval" beam I saw "extreme", but perhaps the "banana" shaped beam is the new standard. It did have a brighter center...
Laser Products is supposed to be sending me two more P90 lamp assemblies, which I will evaluate, and then post my opinions.
I have still received no response about the Customer Service person's comment that the 3 and 6 volt lamp assemblies will also have the same problem in the future. I've asked again.
I am hopeful, but still a little worried, since the base answer still seems to be, "That's the way they are."