I think you may have missed some of the previous citations. To recap:
True dragons have advancement by age; dragonwrought kobolds do not. And there's no meaningful ambiguity in that definition, because
Draconomicon expounds upon it at great length in Chapter 3, explaining that true dragons increase their HD and LA as they get older, while lesser dragons have a set level adjustment and no built-in progression due to age.
The reason I'm talking about kobolds being in the
Monster Manual is because Gruftzwerg has repeatedly insisted that the DM can use this rule
...to construct a table for dragonwrought kobolds and give them a variable level adjustment and progression due to age, thereby qualifying them as true dragons. Setting aside the obvious circularity of this argument (in order for that rule to be relevant, they'd need to already be true dragons without it, or it wouldn't apply to them) and the absurdity of calling in houserules that don't appear in the book and claiming them as RAW—kobolds are in the
Monster Manual, so even if you were to grant all that nonsense, that passage
still isn't relevant for them.