But as the time varies by timezone, we can't start to judge that day 1 of May consists of days 1-12 in JO time. Instead, we must simply say that 1st of May is 12th day of 173 and that's it. As Knight Kaeawc stated, JOTimeOfDay = RealTimeOfDay.
It has to be so, that you can decrypt this thing both ways. Messing with hours is tricky considering this.