# Why scattering state solutions for finite square well potential are 'inherently' asymmetric?

When we calculate bound states for finite square well we use symmetry of the potential and take the solutions as combination of even and odd functions . But we do not use the symmetry at the time of calculating scattering state solutions. What is the exact basis of this specific difference of choosing the method of solution? What if we use the symmetry to make the scattering state solution as the combination of even and odd solutions?