The current calibration procedure needs an improvement. I found that maximum deviation from a true reading can be as high as 0.69%. The goal is to get better than 0.2%. The current calibration procedure is done on computer. Computer takes voltage reads from the multimeter, stores them, then computes appropriate calibration values and writes them into nonvolatile memory in the instrument. I believe a more accurate calibration values can be obtained if the calibration process does not involve a computer. I t has to be done on the handheld device itself.