That's how marketplace is now. If I set a file as 4.6 only, as this is now, you can't download prior versions (4.5, etc.). FWIW, the newest version is 4.6 only because it has a 4.6 feature that will produce an error in 4.5.
But if you want a 4.5 version, I will have to send you via message... not sure it will make any difference too because your install is marked as MARKETPLACE and not custom, so you won't be able to update.