Don't quote me on it, I don't have the game, but those are usually credited to an account.  Your account would then have the time remaining, and the install itself is irrelevant to the equation.

Agreed. I've been playing MMORPG for years and all that really mattets is they have your account setup. Once that happens and you have your game registered with Cryptic, in this case, it doesn't really matter where get the client again. The benefit with digistore, I guess, aside from pre-orders, is they seem to have faster downloads.