Hello Everready,
at my shop we tend to try to err on the side of the "safe" interpretation whenever possible. Ergo, as listed in table 5.3(D1.5-'95) a change in electrode flux combination is considered an essential variable which requires re-testing. Also contained in that table is a requirement to re-test any change in electrode classification. I have not reviewed a newer addition of the code recently in regard to this. Also depending on whom the work is being performed for, they may wish to have some input regarding this. In some states The DOT provides or stipulates a list of approved electrodes that should be considered. These may or may not be "pre-qualified" based on thier interpretation and opinions.
Also of note may be wether or not the work that you are doing is considered fracture critical , if so that can open a whole new can of worms. Hope maybe this helped a bit , Im no expert but I am learning and just trying to pass on some of what I have had to learn in the last few months. If I can be of any further assisatance, please feel free to contact me.
I would say that Table 5.3 Numbers 8 means you would not be able to qualify both wires with the same test. As you have indicated, you will have 2 different electrode-flux combinations. The EM12K and ENi1K are significantly different.
Also, Table 5.1 lists WPS qualification requirements. 5.5 does apply to the manufacturer but 5.5.1 and 5.5.2 apply to WPS qualification. That is the contractor's responsibility, not the electrode/filler metal manufacturer's.
Table 4.3 means that if you are welding Gr 50W steel, the weld metal must achieve a Ni1, Ni2........ or W chemical analysis in addition to meeting applicable requirements of Tables 4.1 or 4.2. Note 3 talks about, again, the contractor's responsibility.
I don't think section 5.4 helps in the arguement that Table 5.1 refers to the manufacturer because 5.4 is only giving the direction that base metal used for WPS qualification must meet certain requirements. It means the contractor must make sure the metal used is in conformance or else the entire test will be unacceptable.
Actually, it sounds to me like some of your folks are getting some D1.1 prequalification requirements mixed up with D1.5. My interpretation is that you need 2 PQRs. (I don't think 960 / L-61 will even achieve a Ni x or W analysis, will it?)
Hope this helps
CHGuilford