Immunization and target rate/yield curve shift

Can someone explain why an upward sloping yield curve generally creates a target rate below the YTM. I understand the reinvestment return is lower, but why? Examples? Thanks

Was this mentioned in Schweser as I don’t remember this?

Check this http://www.analystforum.com/phorums/read.php?13,1093118,1094281#msg-1094281