DxO FilmPack comes with 2 activations. You can download it onto two different computers as long as you are the user of both computers and do not use the two versions simultaneously.
It is possible and permissible to install DxO FilmPack on both a Macintosh and a Windows computer.
Please note that we cannot reimburse you for software bought online that has already been activated. This is standard industry practice. We give everyone the opportunity to use a complete, fully-functional trial version of DxO FilmPack for a full 30 days.
So please do try out DxO FilmPack before buying!