I always start with the entire explosion set to their original position by 1st removing all the default explode positions. From there, I always use the increment setting. Depending on the coarseness of the setting, it is easy to manage. It is also easy to overlook the setting and letting smooth take over again. Then you have to quit and start over. Of course, I am doing this on Creo 2.0. There really should be a config setting that forces increment mode by default. Anyone know if there is one?
Even back in 2000i I was using this function. Somehow it seamed more intuitive then. Either you are dealing with a bug or someone might need to point you to how to use the feature correctly.