Can the maximum pages scanned limit not go higher than 50,000? I change it but it just changes it back.

That is the maximum amount. That size of a sitemap will be around 5mb already, so any larger and the sitemap.xml or HTML will be so huge, it will not really be useful.

The upper limit for sitemaps accepted by Google and other search engines is 50,000 URLs. This is the limit established by "sitemaps.org"
For sites with more than 50,000 URLs, you can generate multiple sitemaps and submit them to SEs with a "Sitemap index file":

http://support.google.com/webmasters/bi … ;ctx=topic
http://www.sitemaps.org/protocol.html#index

Thank you.