Hello Auwis

Generally, when nozzle reinforcement is being considered, ASME Section VIII, Divisions 1 and 2 do not required that the mill under tolerance be deducted. In the case of a seamless tube, the tolerance is for the extrusion process. If you lose thickness on one side of the tube, you gain it on the other side. The nett effect is that you do not really lose any material thickness for this reason.