Like many issues discussed here, the term, "Custer Bomb" is not a simple term.
The link below details the various and varied submunitions carried in cluster bombs.
The submunition that seems to be at issue in this thread is the area denial weapon...I can with absolute certainty tell you that any weapon that had a 40% false submunition rating that was not an area denial weapon would not be dropped.
Weapons testing in this country is so exhaustive and monitored that some of the assertions in this thread are, well, exhausting.
http://www.fas.org/man/dod-101/sys/dumb/cluster.htm