Open Handicap weights in NZ

[Huey]

What a great run from Belardo Boy on Saturday under 62.5kg.

Why does a top weight like that carry over 60kg in an Open Handicap, shouldn't he just be carrying 60kg? Or is the horse catering for those entering Open Handicaps who aren't in that grade?

[curious]

7.1 Open Races
Open races are open to all horses except two-year-olds.
The top weight will determine the spread of the weights, down to the required
minimum. For any transferred horses from another race that then creates a
larger rating spread after declaration of weights than 15 points, the top
weighted horse of 60kg and /or 62kg will remain unchanged. The top weighted
horse is required to carry 60kg for Black Type races.
Non Black Type races. Horses rated 88 or lower will carry 60.0kg. A gradual
weight increase of 0.5kg will apply for horses rated 89-91. Male horses rated 92
or higher and female horses rated 96 or higher 62.0kg at the time of
declaration.