This should not be a topic for discussion because the rule is very clear about it:
2.6.2 The server shall then project the ball near vertically upwards, without imparting spin, so that it rises at least 16cm (6") after leaving the palm of the free hand and then falls without touching anything before being struck.
The important part is:
"...so that it rises at least 16cm (6") after leaving the palm...."
The first part of the service rule, namely, "2.6.1 Service shall start with the ball resting freely on the open palm of the server's stationary free hand" is also important because if the serve does not start with "ball resting freely on the open palm of the server's stationary free hand", it is virtually impossible to judge the toss.
Rule 2.6.2 means that after the toss, the separation of ball and player's palm must be at least 6" before the palm and ball get any closer. We see sometime that after the 6" toss the player's hand follows the ball and gets closer than 6" from the ball as the ball raises, and sometimes also when the ball falls. But as long as the 6" separation of the palm and the ball was satisfied, and the palm and hand is not between the ball and the net (not hiding the ball from receiver), the serve is legal.
Thanks,
Paul