I'd like an official response to this.
I get how you calculate Devils Trident (1 dark 1 fire) to 3 points for a necromancer, 2 points for warlocks, 4 points for a FM / wizard / Siren, and 5 points for a Paladin / beastmaster / druid / Priests.
But IMO your comparing apples to oranges wtfcannonjr.
When your in a specific school of creatures i think its different.
What training rule leads you to believe that the addition of the term Creature (which is only one of six spell types) would change the logic of the other training rules?
For me I consider that being trained in Holy spells means I pay single sbp costs for all Holy levels that apply to any spell card I put in my spellbook. Other schools on the same spell card would then have their training cost calculated using the rules for non-trained SCHOOLS. The training rules do not allow me to pay single costs for other Schools on the card even though it is considered a Holy spell. For example, consider how much a Priestess would pay for a Holy & War school creature. This is considered a Holy spell but the training rules are applied on a school by school basis.
Being trained in Holy Creature spells means that Holy School levels on Creature spells only cost single level spellpoints to place in your book. I read the rule as a training rule exception for only a single spell type. I don't see any rule change that states the other schools on the spell are treated differently for training purposes. For the Paladin, his limitation of Holy level 3 training would then apply to all other spell types but not the Creature spells. In my reading of the rules this has no impact on the other Schools listed on the card which would follow the basic training rules. It is only an exception on how the training rules for the Holy school are applied to Creature spells and nothing more.
Compare this with the training rules for sub-types. I don't have the specific wording handy but I believe they have the added logic that you feel applies in this case at the Creature level. i.e. The specific examples of training rules for a sub-type or Creature sub-type does provide training in ALL schools on that card. For me the added rules were necessary for sub-types since the training language does not reference a specific school and we would have no way to calculate spellpoint costs using the basic training rules. So, a new rule needed to be added so that we can apply the basic school-based training rules to the sub-type training case. However, I don't see any rule that applies this sub-type logic to the entire spell type. Therefore, the base rules would still apply in those cases.
An official clarification would be fine.