Quick question about Conviction / Immunity Breaking

[Zoast]

Can unique monsters have higher light resistances than normal monsters?

(backstory)
I only have level 21 total conviction atm (-130%res), because I'm trying to save all the skill points I can and I dont have torch/nigma and all that ridiculous crap yet.

As far as I know I should be breaking any monsters 125% lightning resistant and below, yet on some unique monsters I don't seem to be breaking immunes. (From the few charts I've seen, the highest listed light resists are at 120%.)

This might be a problem again PILI uniques, as I'm trying to make it through hardcore hell ladder with my light sorc friend and he tried a pure light build (which was certainly not the best thing to do in retrospect). We already ran into a PILI in the mausoleum (we just got to hell and even the pit is a bit too scary) and I couldn't break him.

Also, why do I hear "max conviction is slvl25 (-150%)"? Is that because more levels in conviction against immunes (at 1% per slvl) is just so ineffective or what?
(/backstory)

Basically, should I stay with a lower base conviction and let me final gear take me to 25, or should I finish the skill and have as much -enemy %res as possible? I'm only pvm'ing with this character.

thanks in advance

[Nimbostratus]

Yes, uniques can have higher resistances (or even extra immunities). According to Arreat Summit, the boss modifiers that increase resistance are:

Stone Skin- 50% Physical
"Ghostly" Champions- 60% Physical

Fire Enchanted -75% Fire
Cold Enchanted- 75% Cold
Lightning Enchanted- 75% Lightning

Magic Resistant- 40% Fire/Cold/Lightning
Spectral Hit- 20% Fire/Cold/Lightning


EDIT: After level 25, Conviction's -resistance stops increasing. 150 is the highest it'll reduce.

[Asmodeous]

As far as I know I should be breaking any monsters 125% lightning resistant and below, yet on some unique monsters I don't seem to be breaking immunes. (From the few charts I've seen, the highest listed light resists are at 120%.)

The value of conviction isn't about breaking a 100% plus resistance. See the answer for your next question. There are some monsters with resistance up to 210%. http://www.battle.net/diablo2exp/monsters/act5-abominable.shtml as an example. There could be even higher, but that is one that I know off.

Also, why do I hear "max conviction is slvl25 (-150%)"? Is that because more levels in conviction against immunes (at 1% per slvl) is just so ineffective or what?

The main reason is that a twinked avenger will hit that level easily without spending 20 points in conviction. I think the average is level 17 before items. Against 100% plus resistant monsters, the extra 20% isn't worth much (4% total reduction extra)
However, a monster with one high resistance will have lower resistance to other elements. Have a look at a baal minion for example. http://www.battle.net/diablo2exp/monsters/act5-baalsminion.shtml

Against this, your conviction is worth squat against its 120% fire resistance. But against it's cold (50%) and lightning (33%) resistances, well these will be reduced into the negatives. Now you can see why 150% is much better than 130%. It means an extra 20% lightning damage, and an extra 3% cold damage for what it is worth against baals minions.
Each monster's stats varied wildly, but if you browse the monster stats, you will see why getting conviction as high as possible is worth the points.

[Norrit]

I actually never spend more than 10 hard points in conviction when playing twinked avengers. Between torch/anni, maras(seraph's), coh/valor and HoZ/spirit and some off gcs you can get +15 in offensive auras pretty easily (even more so if you choose to use a weapon like a doom zerker).

At slvl 25 I pretty much break every light immune I've ever found, but against unique monsters with unbreakable immunity you can just use vengeance and hit them with cold and fire.