I've always found when dealing with ICBC for anything anomalous get it on paper and make whatever individual you deal with put their name to it.
the downside to this means you have to go into the office......
It most likely will be one the Prov Commercial Vehicle Inspectors that certifies it as no longer being a "Commercial Bus" and classes it as a motorhome.
Here's another thread of frustration at ICBC's general lack of defined policy and informed personnel working for them.
http://www.skoolie.net/forums/f10/ic...s-13605-3.html