WHS would have been disappointed to drop their first match to old rivals Palmerston North Boys' High School 15-14, but rebounded to beat St Peter's College (Auckland) 26-7, before losing to St Thomas of Canterbury College in their final pool match, 24-5.
In the Bowl competition, WHS lost in the semifinals to St Peter's School (Cambridge), 20-7.
Overall, home team Kelston Boys won the boys' title for the fourth year running with a 19-12 victory over Scot's College.
Hamilton Girls' High took the girls title beating New Plymouth Girls' High 34-5 in their final.
That the Fijian-flyer Koroi was then chosen in the boys' tournament team from a squad that finished in the Bowl playoffs was a testament to his individual performances, given the championship-winning Kelston had four players selected while runners-up Scot's College had three.