Inaccurate?

Sudden Energy Affinity

( Miniatures Handbook, p. 28)

[Metamagic]

You can modify a spell's energy type once per day without special preparation.

Prerequisite

Energy Affinity (MH) ,

Benefit

Once per day, you may apply the Energy Affinity feat to any spell you cast, without increasing the level of the spell or specially preparing it ahead of time. You may still use the Energy Affinity feat normally.

Special

You can gain this feat multiple times. Each time it applies to a different type of energy.