Shaymin LV.X is receiving errata for its "Seed Flare" attack. Seed Flare does additional damage for each Grass Energy card attached during the attack, rather than each Grass Energy attached during the attack. The correct card text should read, "Choose as many Grass Energy cards from your hand as you like and attach them to your Pokémon in any way you like. If you do, this attack does 40 damage plus 20 more damage for each Grass Energy card attached in this way."
Source: Organized Play News (2009-02-26)