There's no major benefit to using HM oil in an engine that has been previously well maintained in most cases. However, the beefier add pack may do some light cleaning if there are any deposits, a HM engine may or may not benefit from a slightly thicker oil, and it wouldn't hurt the seals to maybe do an OCI. It seems people here think you either have to use HM or conventional oil and that you can't go back after using a run of MaxLife or something whereas I think it might not be a bad idea to do a run of HM oil, preferably in summer, to take advantage of the seal conditioners...