E71T11 does have some thickness limitations based on diameter of filler metal but those limitations are not addressed in D1.1.
This self shielded flux core wire has elements in the flux that can be detrimental to a weld. The smaller the wire diameter, the more flux to weld ratio (I Think). Lincolns literature for thier NR-211 had specific thickness limits for different diameters.
However this would not affect the welders performance qualification test if he/she used a qualified WPS.
Table 4.12 does not list filler metal diameter or Electrode class as a variable for performance qualification.
If the procedure were prepared in accordance with Clause 3 of D1.1 the only limitation would be 1/2" thickness as indicated in table 3.1. No reference is made to diameter that I am aware of.
Wire diameter does NOT apply to performance qualification at all. The WPS may be in question but a WPS with E71T11 for 3/8" plate is not outside what is allowed by D1.1. If in production material greater than 1/2" must be used then a different wire would be needed however that different wire would not require requalification of the welder.
JUst my opinion. Find it odd that a consensus of 4 CWI's came up with this decision. Of course there may be other specification in place that are more binding than D1.1 and of course the possibility that I am missing something.
I'm not alone, others too, deal with this kind of stuff.
I had this same issue come up, I challenged it, slapped the Code book on the table and told the Inspector to show me his justification. I was able to talk him back and convinced him it was a WPS concern not a welder qualification concern. You win some you lose some.
Read my post in techincal, and see what else you will come up against. (I hope I'm on base with my thoughts on that issue)
You are right in how you are seeing it, but now you have to play the politics of the industry, who has the most stroke.