Sorting breaks Sass expressions

[okonet]

@each $customer, $width in $customers {
  .customer-logo_#{$customer} {
    width: $width;
    background-position: ($customer-position * -1) 0;
  }
  $customer-position: $customer-position + $width + 5px;
}

becomes

@each $customer, $width in $customers {
  $customer-position: $customer-position + $width + 5px;
  .customer-logo_#{$customer} {
    width: $width;
    background-position: ($customer-position * -1) 0;
  }
}

which is wrong.