Yes, and that is the crux of the debate, and I would accept it if everyone couched it that way. It is not an attribute of the "method" chosen (two part vs using an NaCl free salt mix), but rather how manufacturers actually implement either method. Either method can be perfect, or less than perfect.
It gets down to debating what it means to match natural seawater residue (I actually think this is a serious open question) and what level of matching one may think is useful/desirable/attainable (which assumes folks can even agree on what matching means).
You say you do (or may do) a better job than two part systems do in matching a seawater residue. That's certainly possible. I've never seen any actual data for any of these products. I would caution, however, that such a claim is fraught with interpretation and misinterpretation.
When you say you leave a NSW residue of all trace elements, do you take into account trace elements incorporated into coral skeletons? Coral tissues? Coralline algae? Since even the uptake of the major ions such as magnesium can vary greatly from species to species, what does it even mean to say you match NSW ratio left behind? Behind after what happens?
For the better two parts, the difference from Balling does not relate to massive effects such as sulfate vs no sulfate (at least not for many two part choices reefers make). It is far more subtle and gets down in the weeds of what exact elements are provided, how important they are, and in many cases, perhaps not even agreeing on what is the NSW level of some of the much more obscure ions that vary with depth, location, time of year, etc.