<i>&quot;If it isn&#x27;t in the specification, it isn&#x27;t legitimate, period.&quot;</i><p>You have some goal you&#x27;re trying to achieve, or why was a specification written at all?  If you find that the existing specification is not the optimal path to that goal, you may very well want to change the specification.  In which case, it&#x27;s entirely legitimate.