refering back to a previous cell

[boomshank]

Hello,

I have an issue which i hope someone will be able to help me with. I have attached an example spreadsheet.

When i need is :

On each date for each order number, calculate the number of outputs per form and place the total in the outputs cell for the first entry of the order.

So as an example

Order 1 -
Cell J1 would read 28
Call J2 would read 30

Order 3
Cell J5 would read 39
Cell J6 would read 0

I can accumulate the totals as i go but what i am struggling with is refering back to the first cell and updating it.

Can anyone help please?