The `TimeInterval` is an offset to a `Time` (obviously). But the Time value is a number (usually representing 1970-01-01 onwards in seconds).
Your interval is actually an interval relative to the year 0 A.D. (or a date represented in TimeInterval) which if used with a Time value won't give you what you want. So as @dom96 say, you need to convert `TimeInterval` to `TimeInfo` by hand (because your interval isn't really an interval).
