Bangladesh holidays extend proto making and SXS making. They never extend a supplier's fabric or trim lead time, because a supplier who is working keeps working.

Chinese New Year extends fabric and trims only when that material is sourced from China, widened by the wind-down and recovery buffers.

Fabric and trims run side by side. The later one gates, and only its lost days are counted so a shutdown hitting both is never charged twice.

Reverse works milestone by milestone, then re-runs forward to check the answer, and returns the latest date that still makes the deadline.