Also, a quick shorthand method in the 330 (works on the McBoeing MD11 / B717 box, too) is to just type the number "1" in the scratchpad and drop it in LSK L1 on the PROG page (the altitude field). Makes the current FCU selected altitude your cruise altitude.
True. Not only 1, but whatever altitude is below your crz altitude. Whatever number between 1 and current FL. Concept is, 1 is understood as FL001.