Differences in the extent to which one power clothes itself in another in every place where this occurs indicate whether the action of the wearer is greater or lesser. The degree of action always remains proportional to the extent of the parts of the wearer that are clothed. The fact that in one place a large part of the wearer is clothed whereas in another place only a small part is clothed indicates that the action in one place is greater than the action in the other place in exact proportion to the extent of the parts of the wearer clothed by the garment in each case.
However, as to the reason for the degree of action in any given case – it is because this is what the overall purpose requires. Various reasons could be found for the particular degree of action in any given case, because this has ramifications in various spheres.