Identify Grand Total row

Hi,

I have the following data for which I need to calculate Pallets Count (calculated as CartonCount devided by Units Per Pallet) but:

• if for a given OrderID there is only one ItemCode the Pallets Count should be round up to the nearest intiger,
• if there are different ItemCodes for any given OrderID the Pallets Count should be rounded to two decimal places
• the Grand Total line should show a sum of Pallets Count as visible in the pivot table (with the above rounding rules taken into account) and it should be rounded up to the nearest intiger.

I managed to get the first and second item right but I'm unable to correctly calculate the Grand Total Pallets Count for orders containing multiple line with the same ItemCodes for a given OrderID - in the below screenshot the Grand Total row in the pivot table on the right should show 1 instead of 0,24.

The sample data can be downloaded from here: https://1drv.ms/x/s!AsndWCnO9mGupo4clejyLPORQfILEA?e=xasZ0e