Perhaps it would have been useful if you had introduced yourself properly in the first place.
And (now that you've made all that clear), I can but wonder why you asked the opening question to this thread anyway.
But ... you haven't answered my question(s); you talked about "testing", but now you've mentioned "calibration". OK, but what about "repairs"? Or in other words, what happens when the kit is found to be faulty?
And (about your analogy):- but you
do change the engine oil and the filter!
So I stand by what I was getting at earlier:- "testing" without the possibility of "servicing" as well must be (by definition) a "limited" service. Good luck to you, but to my mind it's a flawed business model.
PHS? Do you mean the people who service toilets? So now I
think I know who you are. But why all the "mystery"?
