Here's the FAQ entry :
QUOTE
Though mystic adepts must split their Magic between Magic-based skills and adept powers, it says that for all other purposes, including the limits of adept powers, the mystic adept uses his full Magic attribute. Does this mean that a mystic adept with Magic 6 who has allocated 2 points to Magic skills and 4 points to adept powers can cast Force 6 spells without flinching?
The Magic points allocated towards Magic-based skills counts for all aspects of those skills. This includes: Magic-linked skill tests (Summoning, Spellcasting, Enchanting, etc.), maximum spell Force, overcasting, etc.
For a mystic adepts adept powers, only the points allocated towards adept powers apply. This includes powers that require Magic Tests like Attribute Boost, the maximum rating of leveled adept powers, etc.
For all other purposesi.e., non-Magic-linked skillsthe mystic adepts full Magic attribute is used: pressing through astral barriers, initiation grade limit, Masking metamagic, being assensed, etc.
So for the example above, a mystic adept with Magic 6 with 2 points devoted to Magic skills and 4 points to adept powers, the maximum Force he can cast at is 4, and anything over Force 2 is Physical Drain. His adept powers are limited to rating 4 or lower.
So yeah, if you limit you "adept magic" to 2, you're stuck with level 2 power at max.