OK. Maybe I misunderstood. But you said that you got the "already synced" message, and that only happens when you try to force an *upload*. It doesn't happen for a download, which is where you said it happened. So I made the assumption that you actually did was upload on the Windows machine and then upload on your tablet too, which doesn't get you what you want.
Sorry if I'm telling you to do what you're already doing, in which case it sounds like there's a bug.
But again, that "already synced" message doesn't happen on a download. At least for me. So I was explaining how to download your flight plan onto the tablet that you uploaded from the Windows machine.