Help - issues with calculating payment stream

Hi,

Could anyone please help me with this problem. Though I have been using PowerBI for a while, I am relatively new to DAX. 

My data model has the following tables and a DateMapping tables, which has a series of dates.

The following is how the tables are connected.

In short, our employees bring in certain contracts and they get a share of the value of the contract either as an upfront payment (value of the contract*Upfront %) at the Contract sign Date. And once the contract starts paying, the employee will get a share of the payment (payment*Residual share%). I am able to calculate the second step – Residual payment. But I have issues assigning the Upfront payment to the Sign Daye of the contract. This is the output I am at –

Note that I am able to pull the Sign Date into the table, (by appending the Contract ID and Sign Date  from Contract_Info Table to Contract_Payments table as Contract ID and Date.. This may not be the elegant way,.. ). However, I need help in getting the Upfront Payment for each combination to line up with the Sign date.

Thank you very very much for your help.

Please do not mind if I have follow up questions on the solution.