DETAILS If you have a time format with a AM/PM indicator then it will take any string between 12:00AM and 12:59AM as being PM. The output from this program is 12:30PM 12:30AM There are some reasonable places where the AM/PM is ignored, when the HH looks like 24Hour clock: 00:30AM is read as 12:30AM 13:30AM as 01:30PM etc From that I would have expected 00:30PM to be 12:30AM but it is 12:30PM. EXAMPLE PROGRAM program time x ('hh:mmpp') compute x = "12:30am" write x compute x = 30*60 write x end program WORKAROUND Set the time to 00:30AM