Hello, I'd like some help. My mage with 3 body is casting a Force 6 Increase Attribute (BOD) spell, and gets 5 hits. This sets her body rating to 8. However, my GM is saying the maximum is +4, so it'd be 7. While the difference is minuscule, I wanted to know who is right? Because from what I read from the spell, the maximum it can increase a spell is number of hits up to the force of the spell.

The GM is correct. For any attribute, there is an Augmented Maximum of +4, regardless of source. The spell even mentions it.

Unfortunately, while the SR5 core rulebook mentions Augmented Maximum a couple times in the magic chapter, never defines it specifically. Even so, it refers to the maximum +4 bonus described on page 94 (regarding buying augmentations).

This is the correct answer. SR4 does it a bit differently but for SR5 this is the way it's done.

I thought that referred specifically to Bioware and Cyberware. Magic goes up to hits = force rating. If the cap is +4, then there's no point in ever casting an Increase Attribute spell in excess of Force 4.

You have to cast force at or above the rating of the attribute you are casting or else it has no effect.

So, if you have logic 6 and want to increase it at all, you need to cast at force 6 for it to even take hold.

I'm aware of that caveat, but otherwise there's no real point then?

Higher-Force spells are more difficult for the opposition to dispel, and are less likely to disappear in an area with a background count.