The offline version simply doesn't have a few of the features that the online version has. It doesn't automatically include your best 10 units (you have to count them yourself), it's missing a few of the older courses, and you can't directly input percentiles (which is what the online advanced version allows you to do).
The formula changes slightly with each version released, and I think the last version was released in April. There shouldn't be any quantitative differences between the online and offline versions.