always use max-age if exists following 1.1 spec

Fetching the cache header is done in wrong order right? If both expires and max-age exists, expires is chosen but should be max-age according to the 1.1 spec http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html#sec14.9.3 

This is happens when different timings is set, check https://developers.google.com/ and the https://developers.google.com/_static/css/screen.css for example:
<pre>
cache-control:public, max-age=600, public, max-age=600
date:Mon, 20 May 2013 09:02:23 GMT
expires:Fri, 17 May 2013 03:08:07 GMT
</pre>