This is a very good point and I agree with this.
In a different circumstance, we as a calibration team, provide a master list of all the instruments being calibrated internally/externally and are stable.
However, with a particular customer, they pull-out their own instrument and replace it with other spare instruments which messes up the Master list. They do this in a very frequent manner (almost 10-15 instruments per week are replaced) and there is no assurance that the instrument they pulled out will ever be returned.
I am looking for a way to exclude them in our Master list since our Test Engineers with direct contact with that customer have their very own Master list of instruments for that account and the control of calibrating the instrument already belongs to the Customer even in their financial budgets for calibration. Would this still satisfy 7.1.5? Provided that the Test Engineers have the Calibration Certificates.
List them separately and REQUIRE that your customer provide a record of the calibration along with the tool.