When we are discussing how many unreleased (and releasable) songs of MJ are left, the number we have is just a guess. For many songs we just dont have any or very few information, like for songs he mentioned in the deposition. And that are not all songs that are complete and releasable before the deposition (we learned that from for example loving you and dream away). As we dont have something like the deposition afterwards there are probably many more songs we dont know off (for History i think there were not so much outtakes).
And then you just talked about the Bryan Loren songs: There should be something between 20 and 28 songs. We know
Mind is the magic (released)
Superfly sister (released)
To satisfy you (released)
She got it (leaked)
Work that body (leaked)
Serious Effect (leaked)
Men in black (demo leaked/more complete version may exist(?))
7 digits (leaked snippets)
Dont believe it (leaked snippets)
Truth about you
Call it off
Serious Moonlight
Deep in the night (leaked snippets)
And additonaly he wrote raps for black or white and family thing.
That makes 15 songs, considering black or white and family thing, if i didnt forgot anything. But do we know anything about the other 5 to 13 songs?