Short answer
Seat allowance increased and the balance re-set so the smile disappears at any angle.
Why it happens
Seat prominence beyond the block allowance.
Why ready-to-wear cannot fix it
Size charts grade uniformly; full seat is a personal geometry. A block adjusted in one place pulls in another — which is why the correction must exist in the pattern, not in the fitting-room mirror.
How the house drafts for it
Seat allowance increased and the balance re-set so the smile disappears at any angle. The correction is recorded in your Fit Passport, so every later commission starts from it automatically.
Where it matters most
This correction carries most for: trousers, suit, womens suit. It is reviewed at every fitting, in every city, for every garment.
Fit Library entry 12 of 48 · Reviewed by Bonturberg Editorial Review · 2026-09-08