Negative Levels & Caster Level

[Jamz]

This is half-rules question and half Hero Lab question... Is there a reason HL doesn't reduce Caster Level when you apply a negative level?

My understanding is your Caster Level isn't actually reduced when you get a negative level (or is it?) but, 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."

This came up because our cleric had 5 negative levels and wasn't applying the neg levels to cure light wounds cause, "hero labs says my Caster Level is still 6" or as we like to say, #herolabsletmedoit

Is there a rules case that "level-dependent variable" would not affect a Caster Level? Or is "Caster Level" a "level-dependent variable" in and of itself?

I mean it does affect concentration, scroll activation, & spell penetration, right? (what else is Caster Level used for outside actual spells?)