I may be wrong but spamassassin does not need to be restarted each time a definition is updated. This is not the case if you use it as a daemon.
Not sure if I understand your manual checking but if you want to see what the latest definitions are in your version of spamassassin visit:
Also, in my original code I tried to get the version of the definitions displayed but never got it to work. That being said the information sent via email regarding the versioning was removed. Currently once a week I get an email telling me if new definitions were downloaded. Otherwise nothing else is done. However, from the operation of my ispconfig server this is sufficient.