For a long time already I have a problem with the rhino plugin.
case in latest Rhino 5 :
1) i make an emitter material with for example power 1000.
2) Later i open the material again to edit and increase or decrease power to 10000 or 100 or whatever value.
3) I click OK.
4) preview updates: looks the same and value didn't change!
I upgraded to v3 and the newest plugin because I thought that could be the issue. But appearently not!
I strongly advise to reevaluate your current development for the rhino plugin. It is very buggy and sluggish on all sides.
Let me know how i can fix this, because I cannot change my lights in my renders this way and as you can imagine that is quite an issue.