Section 21. Except as provided in sections twenty-two to twenty-four, inclusive, and in section twenty-six, if there is a trial in the land court, it shall at the same time assess the amounts due the plaintiff for rents and profits or other damages, if any, and shall determine the amount to be allowed to the defendant for improvements, if any, and also, if duly required, the value of the plaintiff’s estate, unless, on its own motion or that of either party, made before its finding or decision on the title is recorded, it postpones such assessment or determination until after its trial of the title and its finding or decision thereon.