I believe NHRadio is right... WHOM is running at 48KW/3743' HAAT, whereas PKQ is at 21.5KW/3802' HAAT. The addition of 59 feet won't make up for running at half the power.
Another factor, though not nearly as important, since we know the real reason... is dial position, as NHRadio also said. PKQ has to deal with WKNE on the same frequency (94 miles away), closest for WHOM is WSYY some 162 miles away in Maine.
If PKQ could get the same reach as HOM (if KNE didn't exsist), I believe they would have to run their 21.5KW from 5703' AAT. Any engineers out there? I'm certainly am not one... just going off what I believe to be the proper "formula"