Yeah, but the language is identical through the entire template - as it gains HD, its special abilities and spell-like abilities gained increase, but so does the CR...because a creature with more abilities is going to be higher-CR, and thus a challenge for a higher-level party. It should be pretty intuitive, even if it's not a deliberate misreading of the template. Your 'Base Creature' in this case has 20 Hit Dice, not 0, something Zaer had laid out in the initial rules - templates are stacked on top of the base creature, you don't add HD after templates.