Craig, I'm not familiar with the discussion that prompted you to try whisking, but yeast propagate twice as fast aerobically as they do anaerobically, so, by whisking, you're incorporating air and fostering yeast activity. Whisking and adding yeast will both produce the same results, although adding yeast is a lot more measurable. By increasing the yeast count by whisking, it becomes very difficult to gauge how much additional yeast activity you've generated. You could, I guess, whisk exactly the same number of times, with the same hand movement and same intensity, but, to be honest, I think that's more work than it's worth. If you have a quantity of leavening that currently works, adding more yeast to the equation, either by adding physical yeast or by whisking, your fermentation will be altered adversely, as you encountered.