Measurement fails in two predictable places: items that were never recorded, and items recorded without enough detail to price. Out-of-sight contents account for most of the first; generic descriptions account for most of the second. Both are field problems rather than policy problems, which is why they are solved during the inspection and not during the negotiation.
Where the original model is discontinued — routine on electronics, common on machinery — measurement depends on Like Kind & Quality research rather than a catalogue figure.