Fabrizio, the 95% figure is for the entire lens.
Coatings are getting so good these days that even complex designs (such as the ethos) have high light throughputs and no noticeable internal reflections.
As for field aberrations, the picture below shows how plossls compare to a variety of other eyepieces:
As you can see, the field aberrations of a plossl are of a similar magnitude to those of an erfle.
This one shows the field correction of an old Nagler design compared to an erfle.
Basically at f/5, the edge correction of an erfle (and implicitly a plossl) is 10x worse than that of the old nagler design.
The modern day ultra wide fields are a step beyond the original naglers in field correction and light throughput.
There is something to be said for extra degrees of optical freedom.
Also, you might find the following article interesting. It gives a fair bit of history on the plossl and includes a comparison of a few commercial offerings (GSO versus Televue versus Brandon).
The results are quite interesting.
http://brayebrookobservatory.org/Bra...%20Brandon.pdf
fwiw) You can no longer buy them new, but another excellent eyepiece to consider is the old Masuyama. I believe Celestron copied it and called it the 'Ultima'. Whether Celestron bothered to apply the same degree of polish to their glass is something I cannot say. What I can tell you though is that the 42mm Ultima is a noticeably superior eyepiece compared to a Meade 40mm SWA. (albeit with a smaller field of view)
Anyway, if you were thinking of trying a TeleVue, I would suggest that their plossl range isn't the best eyepiece that they produce by a long shot. I'm actually surprised that they still make them. Perhaps it is because they still sell well enough to keep the line going.
~c