"Capability" of methods

Hi all,

this might be a question which might not be assigned to a specific topic.

Assume the follwoing:

There are upper and lower specification limits based an HFE or Usability studies. (e.g. Injection Forces 0N-100N )
The medical device has to fulfil this requirement.
In addition comfort levels were found to be 10N-15N.

Is a method, which was developed to evaluate/judge the 0-100 tolerance range - which allows for releasing the product, capable to judge if the "comfort level" is met as well?

Am I wrong with my idea that e.g. a destructive method which shows a GRR of about 20% and was found to be suitable to judge 0N-100N will never be able to validate a comfort level 10N-15N?

Off topic:
Does anybody have some ideas on differences for test methods w.r.t. to batch release vs. design verification testing?
The other way around: Should there be some margins built in the verification testing that screens for the second specification range?

Thanks
Waeller