Cruise Control - Less is more?
	
	
		I don't see what the complaint is really about...
Today I tried out the same instance on my manual Subaru and it works the same - when increasing speed (either downhill or by pressing the accelerator) and holding the "decrease speed / set" button, the current speed at the time is then what cruise control is set to.
Think of the "decrease speed" as also a "set" button and you will understand why the car does this.
If you want to slow the car down, use the foot brake. The decrease speed is really to decrease the cruise speed on a flat road, isn't it?