In Qlik the decimal part of time is not broken into 24*60*60 secs. What I mean is time(42000.25) will result 6.00.00 hrs. Qlik can calculate the time in millisecond, can you try getting the number whith is equalent to timestamp in milli second then try =timestamp(datetime,'MM/DD/YYYY hh:mm:ss.fff') to print in ms.