It often comes down to the DVM designer and sometimes fabrication or cost-cutting (fewer components). A few years ago, Fluke 87V users noted inaccuracies — greater that specifications (+/- tolerance %) — when SOME meters were adjacent to mobile/cellular site transmitters (high RF field). That issue was resolved with a slight design/fabrication/component change to subsequent meters and those used in that industry (situation). — My original Fluke 87 with model 3 LCD has never experienced RF issues. Found in a bucket, under a seller’s table at a computer fair and speckled with spray paint, my BEST Acquisition at $5.00. Some people cannot differentiate Wheat from Straw.