Forcing time to round to single decimal (flight calculator)

[bmwflyboy]

I need to log flight time. I currently have it set so that I can enter a date and time 5/5/2020 and say 19:03 for take off and landing is 5/6/2020 at 04:23. Which results in 9.3 hours. 19:03 to 04:23 is 9 hours and 20 mins. I need it to say 9.4 (19-24 mins = 0.4 from chart below), not 9.3.

I need to force the times into this format:

1 to 6 = 0.1
7 to 12 = 0.2
13 to 18 = 0.3
19 to 24 = 0.4
25 to 30 = 0.5
31 to 36 = 0.6
37 to 42 = 0.7
43 to 48 = 0.8
49 to 54 = 0.9
55 to 60 = 1

This is slightly different that the way Excel calculates time. If I fly for 1 min, excel will see that as 0.01667 and rounds it to 0.0. But I need it to say 0.1 even for only 1 min of flight.

I hope this makes sense and that I have provided enough detail. I feel that I am almost there, I just need a little boost to get to the end. Example is attached. Thank you for any help!