I know two ISO standards that deal with torque wrenches: ISO 6789 and ISO 5394. If you work in the automotive industry (TIER 1), I recommend that you contact your customers and ask them for their internal procedures: they are specialist in tightening/joints and should have good intenal procedures.
R&R for torques must be made using a special device, because when you tighten twice a joint, the second time its properties have changed. Therefore, the difference between the first and second measurement doesn't reflect only the variation in the measuring equipment but also the variation in the joint.