One change I have noticed between the T2X and earlier models of the Titanium line is the change of the HP seat retainer to Monel. It seems like this would have no effect on the use of Nitrox, it seem like the O-ring in the body of the regulator seals this part from having any contact with the HP gas. Am I missing something and can you explain why this change was made? When Atomic does an upgrade of an earlier model to a T2X is this a part that is replaced? Thanks.