I guess one possible solution would be to have roundup & round down buttons. Pressing these buttons would effectively remove the tolerance from the reading by either adding or subtracting 0.25 to 10% (user selectable) - of the resistor's value. From memory there's about 180 different values in the 5 band 1% range. This is the E? something range (totally forgotten) The more obvious solution would be to database the entire range of resistors. When a reading is taken, the system would basically look for a closest match and display the results. Lot of resistors to catalog though.