What is faulty flat work elevation? Why do you care? You've heard of faulty grade elevation and or wood to soil contact but flat work?
Flat work is any paved or covered surface resting on grade, ie; concrete, brick, stone, asphalt pavers, etc.. Unlike open grade needing 4" deflection or separation from the sill plate frame/wood, flat work reguires only 2" of deflection.
The photo below shows a finish front porch brick flat work installation at or above the exterior wall sill plate framing, vinyl siding and or wood trim. This causes water to be trapped against the exterior wall cladding, interior wall wood framing and or the foundation. Guess what occurs? Abnormal wear, damage, deterioration and or water intrusion.