The quote came from a debate on this forum in 2007, which again appeared in 2009.. There was some reasoned arguements at the time.. I'm not going to re-invent the wheel..
http://www.pprune.org/tech-log/379404-737-vref-ice.html I think the ref to the FMC compensating for ice in " normal landing configurations" is confusing, perhaps they should have simply said the margins are greater than in Flap 15 landing config..