The boy wasn't seriously injured.
Mr Bovaird said he and another dean had spoken to the family of one of the boys yesterday.
He said he didn't know all the facts about what happened and he was leaving it up to the family to contact him when they were ready to talk.
The first incident was viewed by horrified witnesses.
Barbara Donaldson was at her letterbox across the road when she saw the truck, heard a bang, and noticed a white object under it. She raced inside her house to phone emergency services while her husband, Derek, rushed to the boy's aid.
"His body was completely under the front of the truck, with his head sticking out," Mr Donaldson said.
He "gently but firmly" clamped a handkerchief to stem blood from the boy's head, and then asked another person to apply pressure while he went back inside to find a bandage.
Police initially listed the teen as being critically injured, but Acting Sergeant Martin Beeby said last night the boy's condition had improved.
"He's no longer critical. He's got a possible broken shoulder and maybe a head injury," Mr Beeby said.
About 20 minutes after that accident, a 14-year-old student of the same school was hit by a car just two streets away in White Swan Rd.
But he was not believed to have been badly hurt and, unlike the Terry St accident, the police serious crash unit was not brought in to investigate.
Metrolink bus driver David Melville said the 17- year-old had tried to catch his bus from a stop just around the corner of Terry St from Boundary Rd, saying he wanted to go to LynnMall in New Lynn.
He told the boy he needed to take another bus which was pulling up on the opposite side of the road.
"The guy just sprinted across. It happens time and time again."
Mr Melville said he was attending to another boarding passenger when he perceived "a shape rocketing across in front of me and I thought, 'Oh no.' I heard the truck come past and I heard the thump."
The truck came to a halt about 15 metres down the road, having dragged the boy underneath.
Mr Beeby said the 17-year-old had run out in front of Mr Melville's bus without looking.