Items Out Of Sequence.

Hi,

I have a list of store orders that should be picked in store sequence but unfortunately are not 100%.
I need to summarise the compliance of these orders but am struggling to calculate it correctly.
It is fairly simple to manually look through the list and mark any non-compliant items but I have tens of thousands of rows to go through each day.
I attach a simplified version to help paint the picture.

Thanks, Feastie.