Sony says its PlayStation Plus three-tier overhaul has "surpassed our expectations" and that the $160/year Premium tier has grown 18% in the past 12 months (Stephen Totilo/Game File)

Stephen Totilo / Game File: Sony says its PlayStation Plus three-tier overhaul has “surpassed our expectations” and that the $160/year Premium tier has grown 18% in the past 12 months  —  Sony kicks off PS Plus' 15th anniversary by chatting with Game File about the past, present and future …