A petition for administration under Part 5 [Sections 62-3-501 et seq.] may be filed by any interested person or by a personal representative at any time, a prayer for administration under Part 5 [Sections 62-3-501 et seq.] may be joined with a petition in a testacy or appointment proceeding, or the court may order administration under Part 5 [Sections 62-3-501 et seq.] on its own motion. If the testacy of the decedent and the priority and qualification of any personal representative have not been adjudicated previously, the petition for administration under Part 5 [Sections 62-3-501 et seq.] shall include the matters required of a petition in a formal testacy proceeding and the notice requirements and procedures applicable to a formal testacy proceeding apply. If not previously adjudicated, the court shall adjudicate the testacy of the decedent and questions relating to the priority and qualifications of the personal representative in any case involving a request for administration under Part 5 [Sections 62-3-501 et seq.], even though the request for administration under Part 5 [Sections 62-3-501 et seq.] may be denied. After service of the summons and petition and upon notice to interested persons, the court shall order administration under Part 5 [Sections 62-3-501 et seq.] of a decedent’s estate: (1) if the decedent’s will directs administration under Part 5 [Sections 62-3-501 et seq.], it shall be ordered unless the court finds that circumstances bearing on the need for administration under Part 5 [Sections 62-3-501 et seq.] have changed since the execution of the will and that there is no necessity for administration under Part 5 [Sections 62-3-501 et seq.]; (2) if the decedent’s will directs no administration under Part 5 [Sections 62-3-501 et seq.], then administration shall be ordered only upon a finding that it is necessary for protection of persons interested in the estate; or (3) in other cases if the court finds that administration under Part 5 [Sections 62-3-501 et seq.] is necessary under the circumstances.