I've noticed that even when cron downloads the latest script package (Wordpress 3.9.2 for example), when you run the installation script it downloads the script again regardless of whether or not it is the most up-to-date version. Recommend only downloading a package during installation if the package either doesn't exist in the scripts folder or is out of date.
Sir when a new version is available Softaculous only downloads a small package of the script which does not include the (.zip and .sql) files. When atleast one user installs the script only then the .zip and .sql files are downloaded on the server. During installation the other package files are not re-downloaded only the zip and sql files are downloaded.
This is to save space on your server and not to download the complete packages of scripts that are not installed on your server.