The typesetter for the 1841 British edition accidentally replaced hath with had in the clause “Christ hath ascended into heaven”, probably because Christ had already ascended. But the following conjoined predicate maintains the present-tense hath in “and hath sit down on the right hand of God”, even though that event had also already happened. (As explained below, the copytext for the 1841 edition read hath set instead of hath sit.) Also note that hath is used throughout the passage. The 1849 LDS edition restored the correct hath in the first part of the because- clause.
Summary: Maintain in Moroni 7:27 the present-tense perfect auxiliary hath in “because that he hath ascended into heaven”, the reading of the earliest text; the larger passage uses hath throughout.