Multiple IF functions

Hi,

I am trying to make a formula that insert a spesific value if a pre defined cell match another pre defined cell, but that also adds a new value to the return cell if the the cell fulfills another prerequisite..

I am trying to make an IF formula that looks something like this:

IF($P2=T1;$O$2;0)+IF($S2=T1;R2;0).

I also want the formula to return "0" in the cells after the cell where the cells in row 2 matches cell S2. So when the loan in repayed, you wont have any more deductions after the return of the "baloon".

I thought about making a OFFSET formula that moves the cell 4 columns to the right if the mortage is to have a down payment every quarter (ref; row N).

You can see from cell X2 that if only returns one of the downpayments due to the fact that my row nr. 1 states the dates chronological and therefore does not match the "first payment date".

If anyone could help me with this, it would be super!

thanks.