An injector or coil pack is checked by resistance (ohms) Affer the power balance test which cylinders did they state were misfiring as I am not sure from your post. Also are they referring to the Injectors or coil packs? I guess injectors since you state they want to replace them.
Going forward I would do the power balance test and determine which cylinders affect the idle. Then Once this is determined Check the resistance of the injectors and the coil packs. We're the injectors you installed new or used?