Does a Heightened spell bypass Spell Immunity?

Question

Spell Immunity:

The warded creature is immune to the effects of one specified spell for every four levels you have. The spells must be of 4th level or lower. The warded creature effectively has unbeatable spell resistance regarding the specified spell or spells.

Heighten Spell:

heightened spell has a higher spell level than normal (up to a maximum of 9th level). Unlike other metamagic feats, Heighten Spell actually increases the effective level of the spell that it modifies. All effects dependent on spell level (such as saving throw DCs and ability to penetrate a lesser globe of invulnerability) are calculated according to the heightened level.

Would heightened spell bypass Spell Immunity? For example, if a character were immune to Fireball, would she be immune to a fireball that had been heightened to fifth level?

Answer 1

Spell Immunity would still protect from the spell.

• Heightened Spell alters the level, but not the identity of the spell.
• The level cap of 4th is only in regards to choosing the spell protected against. Once chosen, level is not checked when Spell Immunity's protection against that specific spell is put to the test. Spell Immunity instead checks only the identity of the incoming spell.

As you can see, the levels don't actually interact at the time when (e.g.) a heightened Fireball is cast on someone protected by Spell Immunity from Fireball: the spell is still “Fireball” regardless of its changed level and is subject to the “unbeatable spell resistance.”

Answer 2

The answer is already quoted.

The warded creature is immune to the effects of one specified spell for every four levels you have. The spells must be of 4th level or lower. The warded creature effectively has unbeatable spell resistance regarding the specified spell or spells.

If I have a 5th level Fireball, it is ineligible for Spell Immunity.

A regular 3rd or even 4th level Fireball will be stopped by it. But by the letter of the ability, the named spell must be 4th level or lower in order to be affected by Spell Immunity.

SevenSidedDie's answer about 'checking for' is not supported by the rules. If the text of the ability said 'the selected spell must be 4th level or lower', it would be unclear, and could be read either way - but it specifically states that the spells must be 4th level or lower - not to be chosen - but absolutely, to be stopped at all. In English, there is no other way to read the sentence.