Average difference in shipment processing (days)

Hi everyone,

I have this little conundrum which I simply cannot figure out how to solve - even though it may appear fairly easy!?

I have to calculate and visualise the average processing days it takes from when an order is placed, till it is shipped to the customer.

So, I have calculated a third column which is basically the (Excel) NetWorkDays formula (calculates the days between two dates, exluding weekends).

So for instance an order that was placed on 01 Nov. 2022 and shipped on 02 Nov. 2022 would have a net work days of 2 days.

An order that was processed and shipped on the same day would have a net work day of = 1.

So, for all orders coming in, I have a column for this calculation, where most of them will show = 1 

I want the average for this, dynamically in PowerBI when looking on a specific period (usually monthly).

Ultimately this column will contain a lot of 1's and 2's so calculating the average for a specific month shouldnt be that much of an issue?

But this doesn't seem to work.

Does anyone have any ideas?