The site Software Informer, is based on the user inputs, as in when the client is installed on the users' system, the client pulls data of the softwares that are installed, & since there are many users using the same software, the latest version of the particular software (say Program XYZ) will be recorded on the SI server. It will however be matched by the server on the developers website.
Yes out of 5 times, you will match the correct current version atleast 4.98 times.
Cheers. :)