While reading the "Arma magica" part of HOH TL (p. 30 and 31), I read this: "A magus always receives his Form bonus against magical attacks".
I go read the Core book, which says (p 85): "the parma magica, Bonisagus's great invention, is an Ability that grants magic resistance that adds to the resistance arising from a maga's Form scores.
Parma magica adds magic resistance equal to five times the maga's score in the ability to the resistance based on her Forms"
I looked for an example of Parma magica calculation but found not.
Imagine a magus with parma 4 (specilised in Vim), and art of Ignem 12.
Is his Ignem parma equal to:
A) 45 + 12 (form score) = 32 (what i always believed and what my IRL ASG said to our troupe when we started the game.. i find it really easy)
B) 45+ (rounded up 12/5 = form bonus) 3 = 23 (what the HOH TL read in conjunction with the corebook could want to say...)
Edit: while rereading, maybe the quote from HOHTL wants to say: "no matter what, the form bonus used when soaking a spell is always taken in account" [and that is something I already knew], but now that I hesitate between A and B solutions, I want your help because this doubt is somewhat killing me