Since Dagon and Kostchtchie have been given boosts, maybe this warrents boosts to the the Paragons as well?
If by "given boosts," you mean that the DRAGON versions are tougher than the stat-block versions in Fiendish Codex I, that's because the Codex stats only the base-level (weakest possible version) of each demon lord, then goes on to provide tips on advancing them. I haven't played with it enough to see if one can get the DUNGEON versions using the Codex advancement guidelines, but since J. Jacobs wrote pretty much all of this material, I assume it works. It should be fairly straightforward to advance the Paragons similarly, if you're using the Demonomicon demon lords and your campaign requires the Paragons to have stats (I honestly haven't ever used Celestial Paragons as combatants-- only as prestige class patrons!).