Comfort is the easiest thing to promise and the hardest to prove. Ergonomic assessment exists because a seat that feels soft in a showroom can leave you shifting position an hour later.
It looks at the dimensions that decide how a body is held: seat height against the floor, seat depth against the back of the knee, the angle and height of back support, armrest position, and the density of the foam that has to hold all of it in place over years rather than weeks. Those figures are what make one sofa restful to read in and another tiring, even when they look almost identical.
It also explains a decision we have made deliberately: our cushions are specified for support first. A very soft seat is flattering on the first day and disappointing on the hundredth.
Because bodies differ, measurement only takes you so far. That is why we would still rather you came and sat down — the assessment tells us the piece is sound, and sitting in it tells you whether it is yours.