A Fixed Principle may
include any Structural Element, but in assessing whether any Structural
Element may be a Fixed Principle regard must be had to the interests of the
Service Provider and the interests of Users and Prospective Users. A Market
Variable Element can not be a Fixed Principle. The Fixed Period may be for all
or part of the duration of an Access Arrangement, but in determining a Fixed
Period regard must be had to the interests of the Service Provider and the
interests of Users and Prospective Users.