Aging Formulas

Hi All,

Please see the file attached.

Got a bit of a head scratcher that I'm hoping someone can help me with.

I have a file that contains details of orders with an accrual amount, total cost and then the cost split by month.

What I'm trying to figure out is what formulas I need to insert into columns K to P to age the accrual based on the cost data.

My knowledge of accounting is quite minimal to say the least and I just can't work out what the formulas should be.

I have manually inserted values into cells K5 to P5 which will give you an idea of what I am trying to achieve.

If someone could help me with the formulas required, it would be appreciated.

Thanks.