My opinion, based on the Arai Corsair that I just replaced. FYI, Arai's 5 year warranty begins at date of purchase, not manufacture.
My Arai was on year 3.5 of the warranty when it started to feel very loose. I bought a full set of replacement pads ad it felt good again. Just a few months later, when the pads broke in, it felt loose again. I asked my Arai rep and he said the EPS will compress over time from normal use - particularly because one layer of Arai's liner is extra soft.
It may be a load of crap, but I can't think of another explanation for my experience.
2010 Kawasaki Z1000