I'm trying to calculate an hour/minute decimal value from a hh:mm value for sorting and grouping. For example, if the time is 08:25, it should be rounded down to 8, but if it is 08:35, it should be rounded up to 9. I have tried to create a calculated field that refers to the original time field with date type = hours and result type = number, but this does not give me the expected result. 22:15, for example, equals 414286, while 06:49 equals 414343. I thought there might be a fixed number I could divide this by to get a more useful number such as 22.3 or 0.927, but this does not seem to be the case.

Does anyone know how to get the hour/minute value in a recognisable decimal format?