Are a lot of premade spells of a higher level than they should be, or is there something that I'm missing?
I can tell that spell level is often just rounded up to the nearest 5, but that's not all.
Panic of the Trembling Heart, for instance, is a level 15 spell, but from what I understand it's "calculated" level is only 7. True Rest of the Injured Beast is even more egregious, it's level 20 but seemingly "should be" level 8.
I'm not sure why the spell descriptions bother to show a breakdown of the spell's calculated level when the spells might be of a much higher level anyways.
Simple mistake:
Spell level goes 1,2,3,4,5 then increase by 1 magnitude: 10, 15, 20, 25, etc.
So what you compute as a level 7 is in fact level 5 +2 magnitudes = 15, same for level 8, 5 +3 magnitudes: 20.
It becomes a little bit more confusing when you talk about enchantments because:
You compute the spell level of the effect (based on the guideline, range, target and duration)
Then you can add modifiers which are not calculated as extra magnitude, but simple extra level.
For example, a wand of Pilum of Fire (CrIg 20), with penetration of 16 and 50 uses per day. Following the principle above:
Step one: Spell level 20 (Base 10, +2 voice range) as described in core rule book
Step two: Penetration of 16 add +8 and 50 uses per day +6. Those are not extra magnitude, but straight levels. So the final enchantment level is 20 +8 +6 for a total of 34. This enchantment level will be then compared to the magi labtot to determine how many seasons are required to create the enchantment, if it is a lesser item (single season enchantment) or an invested item (requiring opening the item, then as many season as required).
Here is the excerpt from the rule, p114:
To calculate the level for a spell using
those Arts but with different characteristics,
refer to the lists above. For every step by which
a category is raised, add one magnitude (five
levels) to the level of the spell. For every step
by which one is lowered, subtract one magnitude
(five levels).
Below level 5, adding a magnitude only
adds one level, and subtracting a magnitude
only subtracts one level. Thus, one magnitude
lower than level 5 is level 4, and one magnitude
higher than level 2 is level 3.
For example, consider a level 15 spell with
range Voice, duration Sun, and target Group. A
variant with the same effect but with range
Sight, duration Moon, and target Room would
be level 25 (+1 magnitude to increase range
Voice to Sight, +1 magnitude to increase duration
Sun to Moon, and no change for changing
the target Group to Room, because they are at
the same level).