IRAY IOR and Scattering parameter in refraction tab issue.

I'm trying to render transpatent plastic material.

So I'd like to put plastic IOR value in IRAY render

But IOR parameter is stuck within 0~1 range and can't put value over it.

also in the past I remeber I could access Scatter value in this refraction tab.

but this parameter is missing, gone.

Is it because I made wrong set up or is it issue of this new update?

I double checked It's PBR-Metal-Rough-with-alpha-Blending shader.