A person's value set is vast, intricate, and dynamic. Fortunately, an ethical theory does not have to be final and comprehensive to be useful. The ethical theories that get written down by philosophers, theologians, pop psychologists, and management consultants tend to make claims to universality. They imply that the ethical theory can be worked out for once and for all, for you and for me. This, I think, is an impossibility.
Values are subjective.
Hence there is no guarantee that yours will match mine, item for item, detail for detail. In fact, it would be most startling if they did. I think it is important to seek out values that many different people can agree on and adapt into their personal ethical theories. They also simplify the task of communicating our ethical insights and preserving the ethical component of our culture. Ethics is not science.