Just treat it like any other yeast, you will be fine. If you have just harvested the yeast, there is no real need for a starter.
Why they say not to re-use yeast from high gravity beers: The high gravity can cause yeast mutation, and it can start loosing some of it's original properties (it is evolving). It may be more or less attenuative, it may have more or less of particular flavors, it may be more or less flocculant. Chances are that you will not notice any change ..... if you continue to abuse and re-use the yeast you will start to notice a difference.