When you pass a literal & as a word to if or $iif(), it's sometimes hard for the parser to decide if it's a normal parameter or the bitwise comparison operator.

To avoid the ambiguity you can first assign the text to a variable...
  • //var %v1 = 3 & 3, %v2 = ... & ... | echo -a $iif(%v1 == %v2,yes,no)
...or place it inside a $() -
  • //echo -a $iif([color:blue]$(3 & 3) == $(... & ...),yes,no)[/color]