The Monks "Ki Strike" Class Feat gives you access to the Power "Ki Strike", and says the following:
This power is a type of special spell you can cast by spending Spell Points
The section on powers (page 193) says that
Most characters who gain powers from a class feature cast them using Spell Points.
But the Ki Strike Power itself does not list a cost in its description. The Ki Blast Power does not specify a cost, either, but the Ki Blast Feat (from the Monk) does:
You can unleash an impactful cone of force by channeling your ki. You gain the ki blast ki power (see page 234), which you can cast by spending 2 Spell Points. Increase your Spell Point pool by 2.
This leads me to think that "Ki Strike" does not cost any Spell Points to use. Is that assumption correct? If not, how many Spell Points does Ki Strike cost, and where do I find that information?