DF Scroll Requirements?

[RobKamm]

I've been rereading the description of scrolls in DF4 and am not finding an explicit answer. Hopefully someone else here can point me in the right direction. I am trying to figure out if a caster needs to have the appropriate level of Magery/Power Investiture to cast a spell using a scroll. Unless it is universal they clearly need to have the Advantage, but it isn't clear (to me) that they need to have the appropriate level.

The closest I've found is:

[quote DF4:15]...one of three classes: clerical if it bears a clerical spell, druidic if it has a druidic spell, or wizardly if it casts a wizardly spell. It only works for casters of the correct type – the reader needs standard Power Investiture for a “good” clerical scroll, Power Investiture (Unholy) for an
evil one...[/quote]

I understand "standard power investiture" to mean the Power Investiture of good cleric, not necessarily stating anything about the standard use of that advantage. Thoughts?