In that case get it while you can, before they’re retrained by headquarters to correctly follow the regulations.
It may be so rare that the issue comes up that no one cares. The only comparable deck license I can think of is the 2nd Mate to 1,600 ton Master crossover, but now that requires all the chief mate classes and assessments so I doubt many people are trying to get STCW II/2 after just one year as mate. By the time they get all the other requirements they probably have the required 3 years (or really close) anyway.