Why is usually that significant? If a unidirectional bezel is knocked and accidentally moved on the dive, it could possibly only display an extended underwater time. Meaning the wearer will overestimate as an alternative to underestimate immersion time, and in conditions that involve decompression stops, this can be a make-it-or-crack-it https://www.watchesworld.com/frozen-in-time-luxury-watches-for-winter/