With regards to changing the title, I do it whenever it's called for. The page title is what I want people to see and understand at a glance. Change it as you see fit, keeping it clear and succinct. Keyword order may play a role in the ranking, especially for exact searches. Frequent changes are probably not good for most pages.
With regards to the DMOZ listing and Google penalties, why worry? My index title has not matched DMOZ in years. And if I only could get 2 listings... it all has nothing to do with Google. Familiarize yourself with Google Information for Webmasters [google.com] and try to get more rest at night :)