Surges or Steady State?

On a Du or Tri bike leg do any of you have success with a series of surges or pickups in sustained pace as compared with a steady state ride throughout?

Best approach is a steady state, unless the course has rolling hills. Then I find that the fastest approach for me is to surge on the uphills and back off the downhills to recover for the flatlands / next hill. Reasoning is that you can gain more time by working the uphills rather than the down.