When there are less than seven is that because one or more spirits is attempting to control multiple chakras?

Yes, this does in fact take place. As the systems shift and change with time and body function, and in response to the activity and thoughts of the host, the individual chakras will vary in their energy work, and rise and fall with respect to energy they attract, and then how it is taken in. And so the spirits on board may be alert for a ramping up in another chakra and seek to claim that particular one and leave the chakra of current residence unguarded. There may be others who swoop in to attempt to claim it, but they may in fact be able to defend more than one chakra to choose between and keep others at bay. When the total is not seven or more it is because very strong spirit meddlers are on board keeping others out, it is not an indication of a less vulnerable status or greater health and stability of the client, it is more a function of the level of power of spirits in residence.