- Storing times using float_time widget requires extra processing to
  ensure computations are done in the right timezone, because the value
  is not stored as UTC in the database, and must therefore be related to
  a tz field.

  float_time in this sense should only be used for durations and not for
  a "point in time" as this is always needs a Date for a timezone
  conversion to be done properly. (Because a conversion from UTC to e.g.
  Europe/Brussels won't give the same result in winter or summer because
  of Daylight Saving Time).

  Therefore the right move would be to use a resource.calendar to define
  time windows using Datetime with recurrences.
