I think we are mixing several different scenarios.
1. Cruise by cruise power setting (piston and turboprops?)
2. Cruise by target cruise speed (jets?)
In the first case you are adding a constant ammount of ernergy and the speed achieved will depend on the overall energy equation. By climbing 200´ above your cruise speed and then descending and acelerating you are adding more energy than in a normal climb because you are using climb power for longer. I guess the same effect could be achieved if you maintain climb power for an equivalent amount of time while level at the cruise altitude.
In the second scenario you climb at climb power but you cruise at the target speed. This means that the energy added is the necesary to achive the selected speed. Climbing higher and descending to accelerate will only achieve a shorter time at max cruise power or a period of time at a reduced cruise power.