It'd a legal requirement to have a single document detailing exactly the weights on the good on the vehicle being transported.
It should also lay out how it's been loaded, its how the system ensures that we don't put a wheel or axle overweight while remaining within the MAM.
It's why nothing should go on the van that isn't factored into the manifest, and it's a drivers offence not a commercial one meaning you as the driver get the scale 3 fine.
There is a legal requirement to be able to show this.
If they want to actually merge manifests they can, but good luck finding a manager who can do it its actually easy, an inspector should be able to read the manifest and know what you're carrying where, so if for example you had something you are not allowed to deliver they can isolate and track it quickly, it a requirement under the 1988 Road traffic act.
And we all know how little Tesco know about the road traffic act what with the mass breaking of it for decades.