Just to chime in, this was my experience as well. I've only booked CX using AS miles once. It was a week or two ago, what the agent was able to see matched what was available on BA. Fed them flight #s dates, etc. One leg at a time and they were able to book it no problem. Kind of funny, every time I'd feed her the next flight she kept warning me that it might price out as a separate award. Very glad I had researched and read the various resources available so that I was confident in what I was doing. In the end 50K miles and I'm flying business class to asia with a stopover for a few days in hong kong.