I think there may be a bug in the rounding to 3 places, it seems that it rounds to 2 places.
Here is my little test program that shows it. It may be I'm doing something wrong too.

$55 = 55.18975647547689
$rten = Round($55,0)
Print($rten)

$55 = 55.18975647547689
$rten = Round($55,1)
Print($rten)

$55 = 55.18975647547689
$rten = Round($55,2)
Print($rten)

$55 = 55.18975647547689
$rten = Round($55,3)
Print($rten)

$55 = 55.18975647547689
$rten = Round($55,4)
Print($rten)

$55 = 55.18975647547689
$rten = Round($55,5)
Print($rten)

$55 = 55.18975647547689
$rten = Round($55,6)
Print($rten)

$55 = 55.18975647547689
$rten = Round($55,7)
Print($rten)

$55 = 55.18975647547689
$rten = Round($55,8)
Print($rten)

$55 = 55.18975647547689
$rten = Round($55,9)
Print($rten)

$55 = 55.18975647547689
$rten = Round($55,10)
Print($rten)