Yes, it is a VERY big difference between a-star and perfect

Thats why i said to you: you may chose one, wich of them is best for your project

For example, Perfect AI is good for huge static levels and for non-cells games (like CS, Half-life and so on)
A-star is better in dynamic usage and its good for cells-games (like Heroes, KingsBounty, and so on, where characters are placed on cells)

Here is a screenshot from my "cell-game": characters would be placed in the cells on the sides of cube, thats why i chose a-star for this project