I looked up when Michael Bolton first started recording. Apparently it was in the mid 70s. and he used to sing hard-rock/heavy metal(!). Him John Parr are roughly the same age (born 52/53). Not sure who started recording first, but Parr had the big hit before Bolton. I don't know if one of them copied the vocal style from the other. I'm too lazy to research.
This is the Bolton song I remember. Definitely heavier than his other schlock. There may have been other harder heavier stuff but like you I just don't care to do the work of research :hihi: