Notice in the R. v. Vallentgoed and R. v. Gubbins facts (see AB CA) that the instrument(s) were sent to an outside entity for re-calibration. The outside facility should have ISO 17025 accreditation as a testing and calibration laboratory. If police are repairing and re-testing their own machines, then notwithstanding the training at the manufacturer, in Kentucky, that the senior officer has received, they are not ISO 17025 accredited. You might want to speak to a metrologist about this issue.

See INTERNATIONAL ISO/IEC STANDARD 17020
Second edition 2012-03-01
Conformity assessment — Requirements for the operation of various types of bodies performing inspection

at v:
"The categorization of inspection bodies as type A, B or C is essentially a measure of their independence. Demonstrable independence of an inspection body can strengthen the confidence of the inspection body's clients with respect to the body's ability to carry out inspection work with impartiality."

3.8
impartiality
presence of objectivity
NOTE 1 Objectivity means that conflicts of interest do not exist or are resolved so as not to adversely influence subsequent activities of the inspection body.
NOTE 2 Other terms that are useful in conveying the element of impartiality are: independence, freedom from conflict of interests, freedom from bias, lack of prejudice, neutrality, fairness, open-mindedness, even-handedness, detachment, balance.

4.1.1
Inspection activities shall be undertaken impartially.

4.1.2
The inspection body shall be responsible for the impartiality of its inspection activities and shall not allow commercial, financial or other pressures to compromise impartiality.
4.1.3 The inspection body shall identify risks to its impartiality on an ongoing basis. This shall include those risks that arise from its activities, or from its relationships, or from the relationships of its personnel. However, such relationships do not necessarily present an inspection body with a risk to impartiality.
NOTE A relationship that threatens the impartiality of the inspection body can be based on ownership, governance, management, personnel, shared resources, finances, contracts, marketing (including branding), and payment of a sales commission or other inducement for the referral of new clients, etc.
4.1.4 If a risk to impartiality is identified, the inspection body shall be able to demonstrate how it eliminates or minimizes such risk.