Peter the Roman was not part of Malachy’s original writing and account. He stopped at 111 which is the current Pope. 112 or Peter the Roman was added by someone to the second printing but was no part of the first and original account of Malachy.
"The Order of St. Benedict claims this final pope will come within the Benedictine Order, and that he [Pope 112] was placed in the secession line because St. Benedict himself prophesied that before the end of the world, his Order will triumphantly lead the Catholic Church in its battle against evil (the Battle of Armageddon)."
So what Order does the current Pope [Pope 111] belong to???
Curiouser and curiouser, as someone mentioned. It's also at risk of self fulfillment but another piece of the puzzle.