Sorry to be late to this discussion. I’m the colleague that Kandahar refers to, and I feel compelled not to leave him alone in this conversation.
And also apologies in advance if my explanation is pretty obvious (or completely the opposite), I'm unable to find a better way in doing so. While I was writing this reply you’ve made clear your point of view of the MuVi guidelines (which I still feel inconsistent).
My concern predates the last errata, and is focused on the description of Wizard’s Boost. As Kandahar has pointed, the issue is that previously to this change, WB worked differently than the other MuVi spells (Wizard’s Reach, Wizard’s Expansion and Group Wizard’s Boost, the last ones from Magi of Hermes’ Ranulf repertoire), affecting spells 1 magnitude lower as the old guide implied.
The February errata corrects WB somehow, making its description consistent, BUT the other spells become outdated, as they increase the affected spell by 1 magnitude. The description on WR reads:
«The range of the targeted spell increases by one category. You may not affect a single spell more than once with this spell, and the targeted spell must be at least one magnitude lower in level than this spell**. There are ten versions of Wizard’s Reach, one for each Form».
Instead, my thought is that it should read as follow to be consistent after the errata:
«The range of the targeted spell increases by one category. You may not affect a single spell more than once with this spell, and the targeted spell must be at least two magnitudes lower in level than this spell. There are ten versions of Wizard’s Reach, one for each Form».
This takes into account that WR is R: Voice (+2 magnitudes) while WB is R: Touch (+1 magnitude).
As currently none of the spells have changed its description, in my opinion they should be updated to the last errata – at least WR, which is the one included in the AMDE book.
I don’t think that using the wording “spell level” on the guide description need any change or (should) adds more complexity, as any other guideline uses the same terminology (InIm, any ReFo, any other General Vim guideline). Instead, the description of individual spells should be adapted to the parameters used and the level dedicated to the base effect, as any other spell of any other Form. The same case is for any other general spell, such as Demon’s Eternal Oblivion, if a player reinvents it with R: Sight instead of Voice: an increase in the final level of the spell due to a different parameter doesn't reduce the base level of the effect.
«The problem under the old rules was MuVi 10 getting you a level 15 spell, which is metaphysically wrong even if not a major game balance issue.»
David, I understand your explanation of why a target spell should not increase its final level beyond the MuVi base level makes, but personally believe that its born from the necessity to make fit WB with the rules, instead to change WB (as you have stated in the past on this forum), causing a cascade effect which implies erratum on the other spells.
It’s hard to debate the metaphysics of magic with the brain and soul behind Ars Magica, so I’m not going to take that path. Instead, I’m confident to walk the balance one. I think that the need to cast two different spells, the Concentration roll, and the possibility to botch them both if the Concentration roll botches is a good weight on the other dish of the scales. Also, it will be now challenging to use the «total change» guideline’s increment of +2 magnitudes, effectively capping the level of the target spell at level 15 if a MuVi ritual spell is avoided and only usable on your own spells:
- Target spell level 15 +2 magnitudes after MuVi = final level 25.
- A base level 45 allow to change a spell of less than or equal to half the (level +1 magnitude) of the Vim spell.
- Thus, the MuVi spell needs to be level 50 (Base 45, +1 Touch).
This also banish any possibility to use a Creo requisite to make a greater change, as this requisite implies an additional magnitude (for example, adding +3 magnitudes to an InVi magic investigation spell to collect more information, as the Technique, Form and sigil of the caster, as per quaesitorial magic guides, or +3 magnitudes to know Te+Fo and an idea of the effect if it’s hermetic).
Making a specialist capable of this feat with a spontaneous MuVi spell sounds like a real live ordeal.
Finally, one last request concerning the use of MuVi on Ritual spells.
«If the parameters of an effect after it has been changed by a Muto Vim spell would normally require a Ritual, then at least one of the original spell and the Muto Vim spell must be a Ritual. For example, a Formulaic or Spontaneous Muto Vim effect on a Formulaic spell cannot produce an effect that would normally require a Ritual»
At the start of this paragraph it’s implied that only changing the parameters to Annual or Boundary (as the pre-erratum WB description said) will require a MuVi Ritual spell, while the last sentence does not refer to the parameters, but to an effect that would require a Ritual (a D: Mom T: Ind level 55 spell, for example).
Can you clarify if the intention is to avoid using “superficial changes” to affect Rituals? I’m imagining a MuVi 25 spell (base 15, +2 Voice) changing a CrAn 25 (base 15, +1 Touch, +1 Size) that creates a cow to create a pig instead.
Also, I've never really understood how can a spell be of level 16 or 19, if any magnitude beyond the 5th level adds in multiples of 5 levels. It's possible on enchanted items, due to other characteristics (number of uses, penetration levels, special triggers...), but in formulaic or spontaneous spells...?
Unfortunately, I am also of the opinion that it is too late to make the necessary changes to be included in the book. Hopefully, a healthy debate can bring an official stand in order to set this kind of issues for any future product, being it from Atlas of from any independent author.