(a) Meters used in conjunction with instrument transformers shall be adjusted so that the overall accuracies will come within the limits specified in subsections (a), (b) and (c) of section 16-11-120 and section 16-11-121.
(b) Meters installed with instrument transformers may be tested independently of such transformers, provided the electric company applies the corrections indicated by a test certificate exhibiting the characteristics of the type of transformers used and guaranteeing the limits of deviation of individual transformers from the average characteristics of the type; otherwise the meters and transformers shall be verified as a measuring unit.