Distributing Rents to Calendar Year

Gentlemen,

I have a challenging formula problem. I am preparing a leasing model for tenants in a property. The lease contracts are in rental years and, what I am trying to do is to distribute those rental year figures to calendar year to see an annual income. However the formula I wrote has some flaws.

I have identified the problems with different types of tenants in the file.

PS: For those not familiar with real estate rental year contract, means tenant enters the property at a certain date and pays the same rent until its entry date next year. An example:

Tenant A will pay escalating rents of 5, 10, 15 in its first 3 rental years. Lets assume entry Date is June 20, 2008. Tenant pays 5 until June 20, 2009, 10 Between June 20, 2009 and June 20 2010 and so on.