I believe its because the vampire cost increase/decrease is applied before or after everything else. This causes some odd results that are not exactly what people are expecting. Could be wrong.

Vevvev wrote: »

I believe its because the vampire cost increase/decrease is applied before or after everything else. This causes some odd results that are not exactly what people are expecting. Could be wrong.

Blood Mist cost = 964 @ Stage 4 Vamp (24% reduction to Vamp spells) and no cost reductions

964 + 24% = 1195.36 (1196 for arguments sake)
1196 minus 6% at Stage 1 Vamp = 1124, however, Blood Mist cost = 1192 @ Stage 1 (inc. 6% reduction to Vamp spells)

Blood Mist should cost 854 at Stage 4 Vamp (24% reduction to Vamp), but it costs 964??



Exhilirating Drain cost = 3086 @ Stage 4 Vamp (24% reduction to Vamp spells) and no cost reductions

3086 + 24% = 3826.64 (3827)
3827 minus 6% at Stage 1 Vamp = 3597, however, Exhilirating Drain cost = 3817 @ Stage 1 (inc. 6% reduction to Vamp spells)

Exhilirating Drain should cost 2734 at Stage 4 Vamp (24% reduction to Vamp), but it costs 3086??

Wait now I'm understanding it. Yes, some abilities actually do have special effects where they cost less. Elusive mist, Perfect Scion, and Hypnosis all have cost reductions per rank on them. Wish it told you this but it does not.

[edit] ninja'd a bit by the above, but I'll leave this here as it goes through some of the specific examples of the OP

MacCait wrote: »

Hi. Testing a build on PTS and noticed that The reduce spell cost enchantment does not appear to be appllying the corect spell cost reduction on Jewellery to Vampire Skills. Further to this, the 'Infused' trait, also does not appear to be reducing the cost correctly.

It looks like the jewellery reductions are applying to the base stat of the Vampire skill, ignoring the stage reduction of Vampire costs.

Can anyone else confirm this?

Is this a known bug?

Thanks

Added info: Blood Mist cost = 1192 @ Stage 1 Vamp and no cost reductions

1192 minus 203 gold enchantment reduction = 989 (but it's coming out at 1013)

1192 minus 324 gold infused reduce spell cost enchantment = 868 (but it is coming out at 906)

1192 minus 2 X 324 gold spell reduction = 544 (but its coming out at 620)

1192 minus 3 x 324 @ 972 cost reduction = 220 (but its coming out at 344)


Exhilirating Drain cost = 3817 @ Stage 1 Vamp and no cost reductions

3817 minus 203 gold enchantment reduction = 3614 (but its coming out at 3637)

3817 minus 324 gold infused reduce spell cost enchantment = 3493 (but it coming out at 3530)

3817 minus 2 X 324 gold spell reduction = 3169 (but it coming out at 3244)

3817 minus 3 x 324 @ 972 cost reduction = 2845 (but its coming out at 2958)

As far as I can tell the numbers you are getting make sense.

Note: it looks like you have 6% cost reduction somewhere else in your build (Alteration Mastery perhaps?, or 3x light armour?), so I will assume this is present for all the examples. I say this because the starting costs you have listed for Mist Form and Exhilarating drain are 6% lower than there normal costs at stage 1 (confirmed by checking on UESP builder), which lists these as 1269 for Mist, 1016 for Elusive and 4061 for Drain and your values are 6% less than this. (If this isn't the case then I am a little perplexed as to why your values are what they are).

Ok, on to how cost reduction is calculated.
Flat cost reductions are subtracted from the base cost first, and then all percentage reductions are applied multiplicative, ie
Cost = (Base Cost - Flat cost reduction)*(1-percentage reduction #1)*(1-percentage reduction#2)*...etc

Now, note that the values I have pulled from UESP are the costs at stage 1, so already include the vampire cost reduction (this can easily be verified as if I change the vampire stage in the builder the cost changes). So first we have to find the real base costs.
So, removing the 6% cost reduction present in these values to get the true base costs:
Mist Form: 1269/(1-0.06) = 1350
Elusive Mist: 1016/(1-0.06) = 1080
Exhilarating Drain: 4061/(1-0.06) = 4320

Next, calculating the expected cost with the given forms of cost reduction:

Elusive mist at stage 1 with one cost reduction glyph and another 6% reduction from somewhere (which you appear to have)
Base cost: 1350
Apply cost reduction glyph: 1350 -203 = 1147
Apply vampire stage 1 cost reduction: 1147*(1-0.06) = 1078
Apply the other 6% cost reduction you seem to have: 1078*(1-0.06) = 1013 (matches the value you are seeing in game)

Or more simply using the formula above
Cost = (1350 - 203)*(1-0.06)*(1-0.06) = 1013

Repeating for the gold infused version
Cost = (1350 - 324)*(1-0.06)*(1-0.06) = 906

Likewise for drain with one cost reduction glyph
Cost = (4320- 203)*(1-0.06)*(1-0.06) = 3637

These all match the values you are observing in game. I think if I kept doing the other examples they would match too.

Now what does this mean - due to the percentage cost reductions being applied after the flat cost reductions, this means the flat cost reductions actually have less effect if you have sources of percentage reduction.
It also means it shouldn't be possible to ever get to zero or negative cost (unless somehow the flat cost reduction is more than the base cost of the ability, which isn't true for any ability currently in the game)

Take the extreme case like you were trying with mist form and elusive mist, with 3 infused cost reduction (972) plus stage 4 plus seducer (plus the extra 6% reduction you have from somewhere).

Mist Form:
Base Cost 1350
Flat Cost reduction reduces this to 1350 - 972 = 378
Percentage cost reduction then reduces to: 378*(1-0.24)*(1-0.06)*(1-0.1) = 243
(might be a rounding effect here vs the 244 you saw in game)
For comparison, without glyphs: 1350*(1-0.24)*(1-0.06)*(1-0.1) = 868

Or for Elusive mist
Base Cost 1080
Flat Cost reduction reduces this to 1080- 972 = 108
Percentage cost reduction then reduces to : 108*(1-0.24)*(1-0.06)*(1-0.1) = 69
For comparison, without glyphs: 1080*(1-0.24)*(1-0.06)*(1-0.1) = 694

In both cases the glyphs only actually reduce the cost by 625 - ie: not as strong as if you didn't have the percentage cost reduction

The counterpoint is also true - cost reduction glyphs are actually comparatively better if you have sources of percentage cost increase, such as NMA or the vampire cost penalty to non vamp skills.

Hope this explains it all well enough.

MacCait wrote: »

@ExistingRug61 Your explanation was particularly helpful. Thank you

The base build is a Dark Elf Templar, wearing 5 pieces of heavy armour, 1 light and 1 medium, with undaunted 10. Totally forgot to look at passives outside of the class. Doh!

I will re-look at this and see if I can make sense of ot again

No worries, glad I could help.
And yeah the templar cost reduction passive in combination with a bit from 1x light armour would pretty much explain the extra unknown cost reduction I was thought you had when I was running the numbers.

I have had Discalulia since birth, I do the best I can.

For those that answered with insightful and helpful answers, BIG THANKS. very much appreciated. You explained everything well.

Moderators... this site is not letting me 'report' posts for bashing, baiting, trolling as per your forum rules.

@ExistingRug61 particularly helpful. Thanks man!