No I don't think it's as simple as that.
There is a reason the Ethos cost as much as they do!
I'd say more crudely like all optical systems (thinking camera lenses etc as well) newer computer aided design techniques have probably had a greater impact at the edges than in the centre.
Something I did miss in my earlier comment is eye relief, I'm not a glasses wearer so it doesn't impact me much until you get down to very short focal length plossel etc.
As with most things you do get what you pay for, IMHO the biggest mistake with eye pieces is having too many. Better to have 2 or 3 great eyepieces than 10 ok ones.
Buy three:
- Widest field you can get with your scope and maintain a ~5-6mm exit pupil.
- Something which gives a 1-2mm exit pupil (this will be the sweet spot of the scope and your eyes ... should be your most used eyepiece).
- Something which gives you ~200-250x for planets and nights of good seeing. Not often that usable in Australia.