If an agent’s exercise of a power is challenged in a judicial proceeding brought by or on behalf of the principal on the grounds that the exercise of the power was affected by a conflict of interest, and evidence is presented that the agent or an affiliate of the agent had a personal interest in the exercise of the power, the agent or affiliate has the burden of proving, by clear and convincing evidence that the agent acted:
1. Solely in the interest of the principal; or
2. In good faith in the principal’s best interest, and the conflict of interest was expressly authorized in the power of attorney.