If you don't have a normal grip (two fingers, one thumb), the ball has to balance within one ounce in any direction. Since there isn't a normal left/right side, finger/thumb, or top/bottom of the ball, they kinda err on the low side. The least amount of allowable weight is one ounce of finger/thumb/side, that's the standard for balls drilled with "too few" holes.
One ounce in any direction.
SH