Hopefully it is just supply issues and will get straightened out for you folks in Asia.
I love Portra 400. It's my standard neg file (Ektar 100 for times when I want more saturated colors for landscapes, flowers etc.) I don't have any real need for the 160 when 400 gives such great results with a stop and a third more speed (though 160 is a fine film.)
I shoot 800 too but could probably live without it if I had to. I certainly don't WANT to, though.