Originally Posted By: Witto
Now you have twice 64 in your code
substract it directly here
$y = Asc(SubStr($b,$))-64
Now evaluate for > 0
If $y>0 $a=$a+($*$y)

that makes 87:
 Code:
Function a($b)
  Dim $, $y
  For $ = 0 to Len($b)
    $y = Asc(SubStr($b,$))-64
    If $y>0 $a=$a+($*$y)
EndFunction