My dtv channel moved to its rf carrier channel - Why?

I just did some re-configuration of my antenna cables to change some 
splitters - trying to remove attenuation wherever I can.  When I went to 
check by net Zentith a/d converter, the local nbc affiliate (KGW-DT 8-1)
and 
it's weather sub channel (8-2) moved to channel 46-2 and 46-4.  I set the 
box up to re-scan, and it returned with the new channel settings.

Did I do something or do these channel assignments move around sometimes?

Where does the box look to do the associations between the rf channel (46)

and the proxy channel?

Dave