Making Time roll over after 24 hours

here's what i have...

note the time should read 06:42. My goal is to have it read "1 - hh:mm" if greater than 24 hours. When I change the blue cells (A1 & A2), it just rolls over without the day.

To be more specific, when I attempted the format suggested it also alters the time to "0 - 12:42". So not only is it not rolling over, it is also displaying the incorrect time.

Here is my most recent example.

Thanks in Advance,
Siv