The use of off-the-shelf software for SPC analysis can lead to the misapplication of SPC results and incorrect conclusions. This is because the software may not be tailored to the specific processes and nuances of the organization using it. Without proper understanding and training in SPC principles, users may incorrectly interpret the data, leading to decisions that could adversely affect quality. It's crucial for users to have a solid foundation in SPC tools and concepts to effectively use any SPC software and ensure accurate analysis.
References: While I cannot provide direct references to the ASQ handbook, the explanation provided is based on widely accepted practices in the field of quality management and SPC analysis.