"Printing" numbers to the right... nested IF(THEN sequence but can't figure it out

Hi All,

I am trying to create a staffing model where in Month 1, Cost A is applied, in Month 2, Cost B is applied, in Month 3, Cost C is applied... then thereafter it is Cost D, per month, continuous.

Each staffing model is triggered by the creation of a "Pod" of people everytime there is a new install.

So, new install triggers:

Cost A

Cost B

Cost C printed to the right and forward (i.e. across columns)

Any help would be greatly appreciated!