The director may find that a trust business previously authorized by him is no longer a safe and prudent practice for savings and loan associations generally to engage in, or has become inconsistent with applicable state or federal law, or has ceased to be a safe and prudent practice in one or more particular savings and loan associations in light of their financial condition or management. Upon such a finding, the director may in writing inform the board of directors of any or all of the associations engaging in such a trust business that the authority to engage in the activity has been revoked or modified. When the director so notifies any savings and loan association, its directors and officers shall forthwith take steps to cease the trust business (if authority to engage in the activity has been revoked) or to make such modifications as the director requires. The director may for cause shown grant a savings and loan association some definite period of time within in which to arrange its affairs to comply with the director's orders. Savings and loan associations which continue to engage in a trust business where their authority to do so has been revoked or modified will be treated as if the authority to engage in the practice had never been granted, and their actions may be grounds for supervisory action against the association, its directors, or officers.