The 1892 RLDS edition omitted the modifier more before power. The 1908 RLDS edition restored the correct reading with more. There is a slight difference in meaning here: with more, Moroni is saying that Parhoron has had power to impede the progress of the Nephite armies—but no longer.
Summary: Maintain in Alma 60:30 the occurrence of more before power, the reading of the earliest extant text.