Fast Dolphin Kicks or Slower Dolphin Kicks?

As a sprint butterflyer, until recently I never questioned the sort of underwater dolphin kicks I should do: as fast as physically possible, then pop up and go at it hammer and tongs. At my LC Zone Championships I tried something different. I was still dealing with the effects of a virus that severely inhibited my taper period. All my times were quite slow, so with nothing to lose I decided to try an experiment. In my 50 meter butterfly, instead of my usual frantic underwater dolphin, I made the kicks slower and more deliberate, stayed underwater longer, and then kept my stroke fast but under control. The result was a time that, while slow, was significantly better than my other times this meet. It was about 2% off my normal times, but my other races were 4-6% slower. It is clear, as a knowledgable butterflyer suggested, that I was probably "slipping" and failing to grab water with my superfast kicks and stroke. By slowing my kicks and my stroke slightly, I "grabbed" more water and moved faster. I wonder if anyone else can offer an opinion on dolphin kicks and sprinting? It is clear that everyone must find what is best for them - it may be that a slightly slower, more deliberate underwater dolphin coupled with a controlled stoke is best for me. This may not be the best for you. Any thoughts?