Their demise duly promoted Tommy Hill onto the final step of the podium, the outgoing champion claiming third in the overall standings as well.
Very nearly capitalising on Laverty and Lowes's exit to leapfrog them in the standings, Tommy Bridewell's breakthrough season on the Supersonic BMW concluded with another fourth place finish and sixth in the standings, just seven points behind the two Honda riders in the end.
Barry Burrell completed his successful weekend with another top five finish in fifth, ahead of James Westmoreland, who bounced back from his earlier crash to seal the BSB Riders' Cup for the highest-placed non-Showdown competitor.
Burrell's team-mate Peter Hickman completed a successful day for Buildbase BMW in seventh place, ahead of Jon Kirkham and Chris Walker, while Noriyuki Haga's first season of BSB racing ended with a tenth place finish.
Outside the top ten, Jason O'Halloran, Stuart Easton, Patric Muff, Luca Scassa and Michael Rutter picked up the final points of 2012.