Under this intorturtation, all UD/BD is illegal because NO car that wasn't as delivered for it's model year or 100% converted to another trim level wouldn't meet the thought process... Actually rendering the rule moot, no?
I'm on record agreeing with that:
Pardon my ignorance, but if update/backdate is not itself the intent - to allow later assemblies (update) from the specline to be used with older assemblies or in older cars or vice versa (backdate) - than what is the point of having that statement at all?
The letter is in response to some of the seasoned vets DISAGREEING with the common interpretation - and I think that the rule needs to be tightened up to clarify the changing paradigm to the vets, or to clarify the intent to the masses who read it as we do.
I suspect, and hope, that the interpretation will open, not tighten, with the caveat that some speclines will need to break apart. how many depends on where the line between UD/BD and a new model is determined to be.