What is in them, by weight
Every box states its contents as a percentage of net weight, excluding packaging. If a box is forty per cent walnut, the pack says forty per cent walnut, and you can go to the nuts shelf and see what that walnut costs by the kilogram.
There are no sugar-shelled pieces, no yoghurt coatings and no extruded filler. Those exist to add weight cheaply and to stop a mix tasting of its own ingredients.
Packed against the order
Boxes are assembled in small batches when they are ordered rather than held made-up in a warehouse. A mix ages at the speed of its fastest-spoiling component — usually the seeds or the softest berry, never the nuts — so a box that has been sitting is older than any single thing in it.
Single-ingredient gifts
A tin of properly graded saffron or a tray of dates is often a better gift than a mixed box, and frequently a cheaper one. It sidesteps the allergy problem that makes mixed boxes awkward, and it gives the recipient a quantity of one good thing rather than a little of nine.