How to report many Contract for deeds?

Hello,

I have an S Corp that  I sell land and offer financing through. All my financing deals are done with contract for deeds for 2 to 4 years. The land does not go into the buyer's name until all payments are made. Currently I have almost 100 of these contracts. I figure out my profit after the land goes into the  buyer's name by calculating the cost of the land and expenses and the sold price minus expenses. Sometimes I will have a buyer make some payments and than stop, so the buyer never gets the land.

My questions is, I want to report the income per land after it goes into the buyer's name because I do not know the profit until title transfers. I treat the land as business inventory.

 

How would I handle the taxes to accomplish that?