According to the Figma design the Date, Time, and Timezone for both start and end times are kept separately.

The DWD spec example I have indicates that timezone is kept in sync and locked to one.

   "context_ineffect":[
      {
         "datetime_standard_url":"https://www.w3.org/TR/NOTE-datetime",
         "datetime_zone":"UTC-00:00",
         "datetime_range":{
            "start":"1970-01-01 00:00:01",
            "end":"2070-12-31 23:59:59"
         },
         "jurisdiction_standard_url":"https://www.iso.org/iso-3166-country-codes.html",
         "jurisdiction_country":"GB",
         "jurisdiction_subcountry":"ENG"
      }
   ]

For now I've modified and ignored the design in favour of the JSON schema but I'd like to confirm if this is the correct approach.