Why German naval rank equivalences are not straightforward

Why were German naval ranks and promotion dates simplified in the original discussion?

Sources disagreed on some dates, and Royal Navy equivalences that worked in World War I were murkier by World War II. The original discussion therefore simplified the German ranks.

The commenter supplies promotion dates and notes that the Royal Navy once treated some lower German naval ranks as equivalent to a British rank one step higher. That comparison works for World War I, but it had become less clear by World War II, the main period of the original video. Wikipedia and the specialist book used for the video also disagreed on some dates. The titles were therefore simplified amid conflicting references and changing institutional equivalences. When officer careers are compared across navies, translated rank names can hide differences in period, seniority, and function.