ASFKAP has given an overview of the Engineering procedures correctly, as I would expect, The other points are well made, the highlights being IN CAT ONE CONDITIONS, and that it is the Aircraft being checked NOT the facility.
It is also important to recall that in Cat One or Cat Two conditions it is abnormal to have a Protected Cat Three facility so the 'unusual' can occur.
It is only under Cat Three conditions or by special request that you would get a protected Cat Three facility, and therefore be in a position to expect the system to operate TOTALLY as advertised.
As a Certifying B2 Engineer my personal answer would have been different had you been talking about returning an aircraft to Cat Three after a prolonged period of being operated certified to Cat One or Two ONLY.