That's simply incorrect.
If both sensors have the same whole-image noise performance, the noise performance for the larger sensor won't be worse at the same print size simply because it has poorer per-pixel performance. It makes up for this by having many more pixels - the number of photons captured is the same, but the higher-resolution sensor just samples them more finely.
The sensor with the better whole-image noise performance will give you a less noisy image and better noise performance at any given print size. The higher-resolution sensor will also give you more spatial detail, regardless of the print size. The per-pixel noise performance is completely meaningless.
Do you only read the sentences you want to read in my post? What I said couldn't be more correct. I'll help you by putting important words from my previous post in bold.
When going for a large print, I would ALWAYS opt for a larger print with the larger resolution camera regardless of ISO. At that point there is no advantage anymore for the high MP camera because its noise performance will be worse than the smaller, lower MP camera when it's a high ISO picture.
If that's still too hard: I don't care about the same print size, I care about the same ppi. For any given large print I will order in my life, I will target a ppi value (preferably one that's equal to the native dpi of the printer) whether I have a 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 18, 50 or more MP camera. I don't care about print dimensions when I'm going large as long as it fits my wall (since larger prints are more immersive) and as long as the print company can deliver those dimensions, I'm fine with it. With this in mind, each printed dot will consist of the same number of pixels (yes, I know paper doesn't work with pixels, but you get the idea) regardless of which camera is used and this way pixel level performance DOES matter.
I've already shared my view on this many posts ago and yet you keep trying to shove your opinion and/or so called "facts" down my throat. Trust me, it won't work, I'll only get more annoyed (like when a mosquito is constantly trying to bite me). You have your opinion on how noise in an image should be evaluated and I have mine. There's nothing wrong with both views. Either you leave it at that, or we're still replying to each other's posts 5 years from now.
Oh and by the way, I thought this topic was about the 5Ds (R) instead of how one should evaluate the high ISO performance of a camera? This discussion has been going on for way too long. It's about time to get on-topic again, don't you think?