As someone who works in a software company, I may jump in and agree to what greg, jon and leo already said.
File version does not necessarily follow product version. Microsoft e.g., often keeps both versions the same (at least for some office products), but from a neutral view, this doesn't make sense and they don't do it for all applications. If you release a product and bump the product version for all components and you have unchanged files in that new package, which are totally identical to those from the previous version, than there's no reason to bump the file-versions for these. You'd push the product version only and be done. File-version can be seen as a vendor-specific (internal) versioning, while the product version is what (should) concern inventory tools. Additionally, a product version number does not necessarily give a hint on what "named" product you're dealing with. o)
Look this, these are the details of an Microsoft SQLServer 2012 "sqlsrv.exe".
For some unknown reason they decided the file-version to be 2011.11(.)0 and product-version to be 11.0.
Another example is the Windows 7 installation I use right now, it is versioned 6.1.7601. Everything is possible o), just don't expect file-version and product-version to match. If you're lucky, the product version at least, matches what is written on the box, which is the case for dopus.exe and totally makes sense from my point of view.