Does the Pro version give you the source code
No, the pro version is supplied only as a key file
I bought A8Comertical about ~12 years ago, and updated to A8Pro last year.
I like it. auto-LOD generator, resource packer, custom starter panel
For now, Commertical edition is unavaiable (I guess), and if you think update from Extra (and you really love lite-c).... maybe that makes sense, because Extra version has too many limitations