Wherever you have {WA{ replace it with {$WA{.

You can clean up code like this a lot if you create a temporary variable:

sub reportWA{  # $key
  my $key = shift;

  my $NewWA;
  my $stags = $WA{$key}{stags};
  
  unshift @$stags, $WA{$key}{PT}; #insert PT at [0]  -line 110
  $NewWA=$WA{$key}{PT};                      # $periodTotal * 1

  $#$stags = $rnds-1;      # truncate off oldest stage
  for my $i (1..$rnds-1){
    $stags->[$i] *=  10;  #stag[n] = initial * (wght**n)
    $NewWA += $stags->[$i];
  }

  $NewWA /= $rnds;
  printf " %d  %d  %8.2f    %s\n" , $key,$WA{$key}{PE} ,$NewWA,
                                 join (", ",@$stags);
}
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