This time, Rountree finished second in 250cc, while he was fourth in 125cc.
Ajah Sullivan, third in the 12-19 Year Girls class last year, had placings of fourth and then two of fifth from her three races to finish fifth for her division.
In the other results, Riki Wainhouse moved up an age group to finish 13th in the 15-19 Years for 125cc, while Alex Luff Scott was 22nd for 250cc in the same age class.
Troy Bullock, third in Year 12-16 for the 85cc class, finished 10th this time.
Rountree's father Antony said the next major event for these students is the New Zealand Junior Motocross Championships, which will be held in the last weekend of April at the Flips Track near Foxton.