The answer to both questions is 'No.' The 2700 is calibrated through the front panel input jacks, so you never have to unscrew your wiring harnesses or buy extra 'cal only' modules in order to verify and adjust the internal DMM. Simply remove your module(s), then send the mainframe to the cal lab. To make this process even easier, several of the 2700's input modules have 'D-sub' connectors for quick disassembly and reinstallation of your ATE system's cabling. Any offsets due to the module relays are accounted for in the 2700's specifications.