Hi, Eric!
In your case it seems like "so far, so good". You haven't yet been "flagged" for copyright infringement.
From what's been said so far in this thread, it seems YouTube's automatic detection does not discriminate between "commercial"(Bert Kaempfert, Henry Mancini, James Last, etc.), "generic"(Smartsound music) or "self-created"(such as yours or anyone else's music). That's where the problem lies. Even if you were to insert text on your video detailing the origins of the music you've used, I'd suspect you may get "flagged" at some time or other, and the burden would be on your shoulders to prove the source was either your own work or from Smartsound.
As I said, for you, up to this point, it's been "so far, so good" and for your sake I hope it stays that way, but the potential is still there for you to be "flagged" when you put rven one of your own compositions into a clip for YouTube. By rights it should be YouTube's obligation to sort out this problem itself, not dump it on its contributors.
Cheers!
Neil.