I could be wrong in this assumption, but it seems like the Y-levels that NotEnoughResources are giving me for certain ores (most notably sulfur ore) are nowhere near accurate. My guess is that the mod is unaware of changes that MyM may have made to the worldgen and ore distributions. After spending some time looking at NER, it looks like it should be able to pull values from the same JSON files that control the world generation for CoFH Core. If this is correct, I think a simple way to remedy this confusion would be to have the MyM Launcher download the same JSON files that the server uses for CoFH worldgen. Could this be implemented? I really think it would be helpful when looking for certain ores that players might have shortages of.
Even now, it works based on the client-side cofh JSONs. If those are the same as the server-side JSONs (if the server JSONs are default, that is) then the problem doesn't really exist. I don't know what benefit having NER on the server-side would really have anyways.