On appeal from the register, or in a proceeding removed from the register, the orphans' court division may find, upon the testimony taken before the register, that a substantial dispute of fact exists and grant a jury trial. When upon the testimony taken before the register a jury trial is not granted, the division shall hear the testimony de novo unless all parties appearing in the proceeding agree that the case be heard on the testimony taken before the register. In any event, the division may require witnesses already examined and other witnesses to appear before it. The division, in its discretion, may impanel a jury at any stage of the proceedings.