Unispins sideways

I can unispin 360 seat in, fairly easily, so i decided to do it off curbs, as i was told in a post.

But i cant even 180 unispin off a curb, i just cant jump sideways and do it?
Is this normal, any tips, heres my normal 360 unispin. It a pretty bad one though, I just dont have my camera right now to do another one (sis).

My addvise:
take your time and:
practise,practise,practise! :slight_smile: