Well then you have to convert between local space and global space and maybe even screen space to be able to match everything. Setting some position + Vector3(5,0,0) can mean quite a difference when set in global space. Remember that NGUI operates in a very small global area (2 / UIRoot.activeHeight) so you should calculate how much you want to move in localSpace and convert to global.
I think there's a bunch of helper methods in NGUITools and NGUIMath that can help you as well.