Spell-like Abilities and Negative levels

Hi,

Do negative levels affect the effective caster level of a Spell-like ability?

I.e. A Pit Fiend casts its SLA as a 18th level caster: if it takes 9 negative levels, would it be considered a 9th level caster to roll against spell resistance or to calculate the damage of its fireballs?

I would assume it does, since that's the way it works for spells, but I can't seem to find any official ruling about it and the only thing I've found is this article, that says otherwise (even though it's something related to 3.5).
The part of the article I'm referring to says: "A creature retains its spell-like abilities (and its caster level for those abilities) no matter how many negative levels it gain or how many Hit Dice it might lose as a result of those negative levels. The penalties from negative levels apply to any attack rolls a creature makes to use a spell-like ability (such as a touch attack or ranged touch attack)."

Thanks for the help.

Yes negative levels says your caster level is treated as if it was lower. It makes no exception for spell like abilities.

Rules Quote: The creature is also treated as one level lower for the purpose of level-dependent variables (such as spellcasting) for each negative level possessed.

Ok thank you, I wasn't sure it was to be considered "level-dependent" since usually SLA are not really based on the level of the monster, and the caster level for said SLA is often based on HDs or the monster's CR. That 3.5 rule didn't help either.