I did some calculations on how the drop in US asset prices might affect CNP. As you will see, I based this on real numbers from the drop in DPF and DPFI published by Centro themselves.
I came to a figure of 6% for Centro assets, which is close to the 7% for RAT.
Details are here:
http://www.hotcopper.com.au/post_single.asp?fid=1&tid=697597&msgno=3026546#3026546