Been a long time minor operational problem. The data comes from the US so, guess what, the time suits the US requirements. The usual local change, likewise, will suit the local time zone. Australia, for ever and a day, has run the effective time to be in the wee hours when there is the minimum traffic about.
I flew freighters for quite a while and it was always a major pain when the changeover to the new charts occurred half way through a tour of duty back of the clock. Mind you, the benefits of flying freighters, overall, greatly outweighed such minor nuisances.
For the FMS, just meant that we needed to run a manual change to suit the local regulatory time requirements.