Answer
Communication methods were redesigned in later Apps7/Apps7.5 SP4, moving data into the now-standard COMM_METHOD_TAB from several legacy tables, including PERSON_INFO_COMM_METHOD_TAB. The old table was kept around in Apps8 (holding only old, pre-redesign data, no longer updated with new entries — which is why you're only seeing new Communication Method records land in COMM_METHOD_TAB with party_type = 'PERSON'), before being permanently removed in Apps9.