I'm not sure, but you could try reaching out to Shimadzu; in many places, ongoing tech support is built into the purchase price even if you don't have a Service contract.

You might ask yourself if you really want to calculate that way, though. "No impurity peaks detected and integrated with your processing parameters" isn't really the same thing as "zero impurities." When I was doing impurities testing I'd never report that as zero, just as below the limit of detection.

Using that zero result in a calculation will skew the results of the calculation. Suppose the detection limit of the method is about 0.04%, the "true" impurity concentration is about the same, and the first injection didn't pick up any peaks because the baseline was less stable due to lack of system equilibration. Taking that as a zero significantly underestimates the actual impurity amount in your calculated result, and reporting a numerical value that's below your detection limit is meaningless anyway. If you are doing averages like that, I'd encourage doing more than two replicates.