Sorry was away on a trip!
You guys are right it DOES work amazingly enough.
My humble apologies for being wrong on this occasion, still don't understand why it's done like that but it is.
But i get confused by Danny\'s post aswell.
In the 737 it is absolutely impossible to fly away from a MCP selected altitude. The non precision approaches are done by for instance if the platform is 3000\' then select 4000\' on the MCP when level at platform to ARM V/S. Then dial the knob and the aircraft will follow the V/S command. However if you leave 3000\' in the MCP IT WILL NOT follow the command.