Richard-
The calculation actually works in the opposite direction to tht expected, but your assertion is false. 549/180 != 548/179 Not voting for an entry increases its average.
Nonsense. Not voting on an entry has no impact whatsoever on its average. A logo with only 1 voter who assigns a score of 1 has the lowest score even if all other logos are voted on by 10000 people. The numbers 548 and 549 above are arbitrary. New voters can increase or decrease the average by assigning a value on a scale from 1 to 5.
E.g.
3 + 4 + 2 + 1 / 4 = 2.5 3 + 4 + 2 + 1 + 5 / 5 = 3 - new voter increased total
Whereas not voting on the logo does not affect the average at all.
Regards,
Erik