…if he said they are “power exercises” then, no, he isn’t right. They are both linear or “max strength” types of exercises. There isn’t really a way to train speed strength with a normal barbell squat or leg press.
But that really isnt the point (just semantics). Leg press works the quads, hams, and glutes. Squats work the same. The only thing that you should really be looking for is over/under-training your muscle groups. We already talked about sets and reps in your training program thread, so I wont go there again.
Go by these guidelines when you are looking at strength.
You need to have a good mix of various types of strength workouts. It’s hard to tell you not to do those two exercises on the same workout, it could be just fine. You just need to remember not to do the same type of strength work every time you lift.