Sorry, no way. Human vision has a logarithmic response.
I agree that the likelyhood that even the very very best observer can reliably differentiate between much less than 10% brightness variation is unlikely.
On the other hand, I think that I have to interject this. I believe that some of the discrepency is they way we look at the numbers, and we tend to do this with an "Absolute" scale of "100%" so that any eyepeice that is between 90% and 100% would appear as bright.
Since the highest transmission is 97.9%, you kind of want none of your eyepieces to fall below a loss of 0.1 magnitude, or 10%, which says it should be at least 87.9%
But that is not the way it works. You really have to start the differential from the lowest transmission eyepeices and add 10% from the bottom.
In other words, if you started with an eyepice with 88% transmission, you would have a "Baseline" brightness as compared to the 100% absolute.
But to see a difference, you would only have to be 10% brighter than this baseline.
So, if the eyepeice started with 88% transmission, and you added 10% to that, you would add 8.8% transmission.
Now my math may not be perfect so this is more about the idea. So, this means that if I can see a difference of 10%, if I use an eyepeice with 88% + 10% of that baseline brightness, I would come up with a relative transmission of the sum of the two. So, a 10% brightness increase from the baseline would be 88% plus 10% of that (8.8%) for a total of 96.8%. So, the step between an eyepeiece with 88% transmission and one with 96.8% transmission would perhaps be at the edge of the range of detection for some individuals, but perhaps not all.
Anyway, we can't look at it as a fraction of 100%, but as the amount of light increase from the baseline eyepeice and add 10% to that number.
And using this, I could indeed see people detecting a tiny brightness difference. But these two eyepieces would have to be seperated by between 8.8% or more in "absolute" transmission.
My own experience is that the difference in brightness is so tiny and difficult to see that it is basically meaningless and no one should worry about this with modern eyepcies.
But some older eyepecies did seem dim to me. Most notably, the Meade 8.8 UWA and a Meade 6.4mm Plossl (Contamination in the cementing between the lenes on the plossl. In other words, a defective unit. I think the Meade 8.8 just didn't have modern enough coatings).
Mostly, modern wide field eyepces though seem to be on par with simpler types to me in brightness. If there is a difference, it is very, very subtle.
Anyway, this explains has at the extremes of transmission, it could be possible to see without 10% seperation on an absolute scale, but I still believe that while there may indeed be individual cases where we see an eyepeice with below 90% transmission compared to some of the eyepieces with the highest possible transmission, most eyepecies today have better than this. Not all, but most.
But using the logic above, I can see how an 88% transmission eyepeice could be detected when compared to a 96.8% transmission, and clearly some of the better eyepcies have this level of transmission.
If somone measured a T6 Nagler and it had 88.7% transmission, then yes, an eyepeie with (88.7 + 8.7) 97.4% transmission should be able to be discerned by someone doing very careful comparisons.
Will it make a difference in viewing? Maybe. I an not inclined to worry about it though. Given that every eyepiece design in production today is diffraction limited at the center of the field, to me personally, all of the meaningful difference in eyepiece performance is to be found off axis. Here, differences are titanic and easy to see, and for me personally have a huge impact on how I perceive the field. But a barely detectable change in brightness (.1 magnitude) provokes a big yawn from me personally.
But someone saying that they can see the difference between a .92% and a .97% transmission? I for one don't believe it.
I do feel as if seeing the difference between an eyepiece with 88% transmission and 97% is indeed possible even thought they are not seperate by 10% of the total brightness because it is the relative brightness differece starting with the lower transmission unit.