Using the Statistics post processing step, you can take the average of many curves and use this average to create limits. This will create a limit that is less rigid in adhering to one specific curve, and will in a sense be adapted for a common behavior of your DUTs. This process of creating limits can be performed offline.
The Offline statistics step reveals all data in the memory list, and can be open through Offline > Statistics > Offline.sta. Selecting the Data option will enable the curves in the memory list for calculation. Ctrl+click, or shift+click to select all applicable curves you want to include in the average. The mean of the curves will be calculated and the resulting average curve will appear in the memory list.
Creating limits from this curve average involves using SoundCheck's curve offset function in the limit editor. In the limit editor, select the average curve in the data selection dropdown. Create the upper and lower limit by selecting copy, then inputting the Y axis DB offset level, and selecting offset. Once Apply is selected, these limits will appear in the memory list. These limits can be used within a sequence to test subsequent DUTs against an average of measurements.