There's nothing like a good Machlokes to help clarify a subject.
A couple of brief points in response (with an effort to stick to English and explain terminology except in highly technical parentheticals that aren't necessary for the primary discussion):
1. It's rather odd that the OU would state one temperature on their website and in the policy sheets given mashgichim, but follow another in practice. Is it possible that the higher requirement was imposed by the local mashgiach, rather than the OU?
2. I used the word simmering in the colloquial sense of liquid that's almost boiling but not quite, rather than the precise scientific sense of bubbles forming on the bottom but cooling as they rise through the cooler water. Like you pointed out earlier, the cut-off temperature is arbitrary--as is any legal rule--rather than based on a precise scientific measurement. The various poskim impose different cut-offs as to what level of heat is required to have recognizable evaporation.
3. As discussed in my previous post, Rav Moshe's opinion is based on the standard of "yad soledes," which is defined in the Talmud as hot enough to scald a baby's belly/cause someone to withdraw his hand (there is a disagreement whether those definitions are equivalent but that's not relevant here). Hence, the whole discussion of evaporation, etc. wouldn't really be relevant. (Although Rav Moshe conceptually accepts those Rishonim--whose opinion was accepted as normative p'sak--that cooking/evaporation is required, he looks to the laws of shabbat to define cooking, rather than any empirical standard of evaporation. Hence, the discussion focuses on the temperature of "yad soledes" rather than the temperature of recognizable evaporation.)
4. Applying the terms "b'dieved" and "l'chatchila"to "yad soledes" causes much confusion. The better terms are l'chumra and l'kula. Since we cannot precisely determine "yad soledes" we consider a range of temperatures. The bottom of the range will define the temperature to which cold (raw) food may not be heated on shabbat. The top of the range will define the temperature beyond which food will be considered cooked and one will be allowed to increase its heat. Similarly with regards to kashrut, the low range of yad soledes will define the temperature at which vessels coming in contact with non-kosher or meat with milk create a problem and must be kashered. And the top of the range will define the minimum temperature necessary for certain kashering processes (the details of which are beyond the scope of this discussion) for which yad soledes suffices. So to summarize: since we cannot determine the precise temperature of "yad soledes" we use a lower temperature when we must avoid yad soledes and a higher temperature when we need "yad soledes."
However, the range CAN BE quite wide if you factor in all opinions--with the bottom of the range as low as 104 according to some--so the question among the latter-day decisors is what opinions can we ignore and which we factor in to arrive at a range that we will use in practice in the manner previously explained. Most opinions cluster around 120F for the low range, so some may set the range at 120-160 or so. However, Rav Moshe is machmir (stringent) and sets the bottom of the range at 109. Further, in various responsa, he cites different numbers for the top of the range: 160F, 165F, and 174F. However, Rav Moshe's opinion has not been accepted in this matter and almost everyone is lenient up to 120F (or at least 113F for some who follow Rav Auerbach) and above 160-165.
As applied to wine (according to Rav Moshe), in order to ascertain the minimum temperature to render a wine mevushal, we look to the top end of the range, which is why I observed that the OU's position is curious in that they follow Rav Moshe in applying the yad soledes standard, but then use a temperature for that standard far in excess of the normative temperature based on one responsa of Rav Moshe where he writes that above 174 is certainly yad soledes--when the OU itself considers 165F the top of the range in much graver matters than wine, such as shabbat.
"B'dieved" (ex post facto) would only come in if you had heated a wine to a lower temperature than required l'chatchila (a priori)and it was already touched by a non-Jew
, then the question becomes how low a temperature could you accept as mevushal in order to save the wine. (After all, the range is due to sofek and stam yainom is an issur d'rabonon, so applying the rule of sofek d'rabonon l'kula, perhaps following Rav Moshe's shita, one could be meikel at a lower temperature than would be required l'chatchila, but that's a complex shaila and way beyond the scope here.)
5. As for the opinions of Rav Auerbach and Rav Elyashiv, I don't quite understand what you wrote but let me try to clarify: Firstly, the opinions must be distinguished but in order to do so, we need to recap some basics (for those who are unfamiliar):
There are 2 reasons given why ChaZa"L (the Rabbis of old) forbade wine touched by a non-Jew (stam yainom):
i. Because he may have used it for idolatry, thereby rendering it Biblically prohibited (yayin nesech).
ii. In order to prevent socializing, which could lead to intermarriage.
Likewise, there are 2 reasons given why mevushal wine was excluded from the ban, each of which relates to one of the previous reasons for the ban in the first place:
i. Because cooked wine was deemed unfit for sacramental use by the pagans.
ii. Because cooked wine was very uncommon in those times and there is a general principal that ChaZaL's decrees did not apply to the very uncommon.
Now let us return to the two opinions objecting to deeming pasteurized wine mevushal (completely separate from the temperature issue). Rav Elyashiv's opinion turns on the prevalence of cooking/pasteurizing wine. He states in his responsum that he was informed that wine is routinely pasteurized. Therefore, he reasoned that pasteurized wine would not be included in the category excluded as "very uncommon." Rather, we'd have to apply some additional unusual process (i.e., non-routine cooking--not pasteurizing) to render the wine mevushal. Rav Elyashiv's opinion has been universally rejected by other leading poskim (decisors) as premised on errors of fact and law: The factual mistake is that wine is not in fact routinely pasteurized. The legal "error" or disagreement is premised on the general rule that we don't extend ChaZaL's decrees. (Rav Ovadia Yosef is very emphatic on this point in his responsum on the matter.) Therefore, if the original decree exempted heated wine as uncommon, it makes no difference whether such wine is common in our days or not.
Rav Auerbach's objection to pasteurized wine applies to the first reason. Rav Auerbach reasons that since an average person can't differentiate pasteurized wine from unpasteurized wine, how can the proverbial pagan know that the wine is unpasteurized? Therefore, we cannot be sure that a wine has not be used for idolatry unless it is recognizable as cooked: i.e., that its taste and/or appearance has changed. (N.B. It doesn't have to be worse--merely different. Hence, I don't get the relevance of your discussion of "profiles" and whether it's "worse" or "better." In any event, I find it hard to believe that cooking a wine to the point where it looks and taste different can actually improve the wine. Am I wrong?) Others have argued that with increased wine appreciation and knowledge around the world, many ordinary people (experts don't count) can distinguish between mevushal and not mevushal wine. The flip side to that argument is that the best wineries have now perfected their processes for flash-pasteurization to the point that even experts can't always differentiate...
In any event, Rav Auerbach never gave a hechsher and I don't believe any of the hechsherim in the world follow his opinion. If followed, it would require essentially ruining the wine in order for it to be mevushal.