Conditional Format in pivot table ??

[Oly Steel Man]

I'm using a pivot table to display part numbers in rows, due dates in columns, to show quantities due for each item on each day. I also have an inventory column for each part and want to highlight the first order where I encounter a shortage. For example row 31; part number is 3040677, due dates as follows, 1/19 - 56, 1/24 - 50, 1/25 - 32, 1/26 - 60, and I have 156 available. So I want excel to highlight cell AJ31 which is the 1/26 order for 60 because I will have a negative quantity of 42 on that day and all other orders after that day. I attached my sheet so you have the raw data to work with.