What the difference between "exclusive" and "leasing" beats?

LaJProd wrote:

Destinite wrote:

BGBEATS wrote:

non big name producers can get approximately 3500 to 7,000 us dollars for exclusive sales to big name artists. These numbers come from two guys i know one placed track with 50 cent the other with busta rhymes. ( as seen above, the busta track has never been released yet the 7,000 was his advance payment)

Now - I'm clueless as to the biz side, as I make beats for myself to enjoy first and foremost, but in the above case, wouldn't it be smart to charge a percentage of whatever profit in addition to the 3500 to 7000? Say the track blows up and this dude you sold to made 100,000 off it and you're sitting there with not even 10% of that?

http://en.wikipedia.org/wiki/Royalties