Type1 study isn’t OK yet.
It seens that your problem maybe the product you are testing for type1. What you need to do is, take a bare PCB and connect all measurement testpoint to a stable voltage source. Measure the voltage at all testpoints, and use that as reference value in minitab. But be aware when you are taking these reference values, to use the same stimuli(Load and shorts). The reference values must not be measured in the measurement system.
When you then are writing the MSA report, then please describe what you have done, to do this type1 study.