Mystic Adept questions Options

[forgarn]

In the SR4A book there is a section that states:

For every point of Magic invested in physical abilities, the character gets one Power Point that she can use to purchase adept powers. Every point of Magic invested in mana-based abilities grants the character one point to use with Magic-based skills. For all other purposes, including the determination of the maximum level for adept powers, the character’s full Magic attribute is used. Such a character will not have as many adept powers as most other adepts, nor will they be able to cast spells with the same skill as true magicians. Mystic adepts may use their adept powers normally.

Now I have a player with a MA and a Magic of 6. He has used 3 points for adept powers. We understand that he only throws 3 dice when making a Spellcasting check, but what is the max power of the spell he can cast before over casting? Is it still 6 or is it 3? The above is kind of vague.